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The Augmented Spherical Wave Method An Extended User Guide

1. dk dk dk Gb dt Gk 3 2 PLOT PROGRAMS AND SHELLSCRIPTS 71 if s 1 then echo grep started on 1 grep converged after 1 tail 1 grep Start of Iteration 1 tail 1 grep irreducible k points 1 tail 1 grep Fermi energy MTZ 1 tail 1 grep band gap 1 tail 1 grep DOS at Fermi energy 1 grep 1 Ryd tail 1 grep Magnetic moment of UP atoms 1 tail 1 grep Magnetic moment of unit cell 1 tail 1 grep Unit cell deviates 1 tail 1 grep square 1 tail 1 grep Madelung energy 1 tail 1 grep Zeeman energy 1 tail 1 grep total 3pV 1 tail 1 grep virial energy 1 tail 1 grep variational energy 1 tail 1 grep qdiff 1 tail 1 grep ediff 1 tail 1 grep ended on 1 echo else echo usage susan filename fi Typing e g susan outlst30 will generate the following about a 20 lines on screen see Sec 2 1 2 including information about the k space grid the position of the Fermi energy the DOS at Er the total magnetic moment the variational total energy and the self consistency level already reached as coded
2. 93 453 Token UNEVS 2 eum werner 93 4 5 2 Token ALAT 93 4 5 3 Token PLAT 93 AS A gt Toke SEATS ala keg E 93 4 5 5 Token BBYA ance elk s diae diets Sem a 94 43 koken BRATE 24 2 gy BE x 94 Tho Token CBYAS este mie IDEA I 94 Token SEAT ir ur cess oe eme ur ut e ze 94 45 9 Token GAMMA s 94 Category CLASS 94 4 6 1 Token NODASSS ee 95 4 6 2 Token ATOM mandatory o ue ak ne 95 10 9 Token Z 95 4 0 4 Token R uu ERR RR Ren RG Soter 95 46 5 Pokemon ES Te Re qoi Des 95 40 0 Token OMX vo ides bd REVERSE E IIS 95 4 6 7 Token 96 4 6 8 Token CONF 96 4 6 9 Token COORB 96 Token QVALS are 96 40 11 Token MENO Desc ue Som te tee au 96 Category SITE 96 4 7 1 Token NBAS A a E A x 97 47 2 Token CARTE uu Eh ano 97 47 3 Token CHOUT 97 4 7 4 Token ATOM 97 4 8 4 9 4 10
3. Distributed Queuing System DQS and Sun s Grid Engine SGE specifications Specify job queue q dawai_express Specify CPU time and memory 1 qty eq 1 runtime ge 600 memory ge 256 1 memory ge 256 Specify start from the current working directory cwd Specify stdout and stderr o job out job err 3 1 MAIN PROGRAMS AND SHELLSCRIPTS 67 Specify the shell S bin bash Export all environmental variables 4 V Mark the job not restartable 4 r n Suppress any notification m n BINDIR HOME asw aswhp BINDIR mnmpr run gt outmpr You may have a look at this prototypical shellscript before adapting any of the other scripts 3 1 3 mnsym run mnsym x This program reads in the CTRL file and performs symmetry check of the crystal structure Alternatively depending in token GENPOS it builds the full unit cell from a minimal set of atomic positions and the symmetry generators given in the CTRL file In both cases the result is printed to file outsym and a file CBAK is created w
4. 103 dip Token a ure us 103 41 5 Token NDOS zie as amp 103 4 11 6 Token NORD 103 4 11 7 gt Token WIDTH Aso ext e 103 4 11 8 Token EFTOL 103 4 11 9 Token 104 4 11 10 Token 104 ra RS 104 Token NES PED ooi Rok ra a RS 104 4 11 13 Token TEMPFD 104 Category 105 4 121 Token START 25 5 A dise e Hu mom dud rus 105 ae 106 4 12 3 Token FREE 106 21719 1 Token NEFBND 3 2 BE u u A Yr 106 4 125 Token CNVG 26 ti deem y ius 107 4 12 6 Token CNVGET 107 412 T Token NITALM 107 4 12 8 Token CNVGQAS 107 CONTENTS 4 13 Category MIXING 4 13 1 Token NMIXB 4 13 2 Token BETAB 4 13 3 Token INCBB 4 13 4 Token 4 13 5 Token 4 14 Category SUPCELL 4 14 1 Token ALAT 4 14 2 Token PLAT 4 14 3 Token SLAT 4 14 4 Token BBYA 4 14 5 Token BLAT 4 14 6 Token CBYA 4 14 7 Token CLAT 4 14 8 Token GAMMA 4 14 9 Token EQUIV 4 14 10 Token CARTS 4 14 11 T
5. 2 3 2 Spin degenerate calculations 2 3 3 Spin polarized ferromagnetic calculations 2 3 4 Spin polarized antiferromagnetic calculations 3 Organization of the ASW program package 3 1 Main programs and shellscripts 1 1 Unnnmpr run mn pre Ware re a 2h Ten 3 1 3 mnsym run 31 inet Tine loe uu i rdg RUBRO rn Dole suu tem ange di E 3 1 6 mnpac run 3 2 3 3 3 4 4 The 4 1 4 2 4 3 CONTENTS uni FM ae ra na 68 3 1 8 Eee Xue ee 68 dub Mds Ra cov uuu Sh ca weg oce i fe onu ur 69 3 1 10 mnbnd run 69 SLIL ERE uo ne a urs 69 2 112 f mscl rim qnnsckx 54 4 dors ae x hd de En 70 IRIS MDF EC uetus a X eet Eos ESSA 70 Sul db SUBAE oe Yh aed dE ue abigo a enu nme 70 Plot programs and 71 32 Plate 8 A u ee 72 522 pre run prex 5 3 6 ae a ei En 72 Did de cplbidobun PlEnd fe he ho Epod Weeks 72 0045 nldosrum ples se ang 73 pleopiX qn
6. 1 POS 0 000000 0 500000 0 250000 ATOM E1 POS 0 000000 0 500000 0 250000 1 POS 0 500000 0 000000 0 250000 ATOM E1 POS 0 500000 0 000000 0 250000 2 POS 0 176474 0 176474 0 500000 ATOM E2 POS 0 176474 0 176474 0 500000 44 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES ATOM E2 05 0 323526 0 323526 0 000000 ATOM E2 P08 0 323526 0 323526 0 000000 POS 0 218838 0 411732 0 355939 P08 0 218838 0 411732 0 355939 POS 0 281162 0 088268 0 144061 POS 0 281162 0 088268 0 144061 P08 0 411732 0 218838 0 355939 POS 0 411732 0 218833 0 355939 POS 0 281162 0 088268 0 144061 POS 0 281162 0 088268 0 144061 POS 0 411732 0 218838 0 355939 ATOM E3 P08 0 411732 0 218838 0 355939 ATOM E3 05 0 218838 0 411732 0 355939 POS 0 218838 0 411732 0 355939 POS 0 088268 0 281162 0 144061 POS 0 088268 0 281162 0 144061 ATOM E3 POS 0 088268 0 281162 0 144061 POS 0 088268 0 281162 0 144061 To be specific 24 empty spheres of three different types have been added with radii ranging from 0 78 to 1 76 ap 2 3 2 Spin degenerate calculations With the complete CTRL file at hand we are in a position to perform the self consistent calculations for non magnetic CrO by typing mnall x at the systems prompt A
7. ck FK FK FK FK FK K FK FK FK FK FK FK OK FK K FK FK ook K FK K KOK gt K K ASW software package KI Version 1 9 Berk kk Copyright notice FA A 2k 2k 2k 2k 2k kk kkk kk FE A A A A AAA A AC A A A A I The ASW software package was written by Volker Eyert In setting up the package the author has benefitted from experience gained during stays at the following institutes Institut fuer Festkoerperphysik TH Darmstadt Hochschulstr 6 D 64289 Darmstadt Institut fuer Physikalische Chemie TH Darmstadt Petersenstr 20 D 64287 Darmstadt Max Planck Institut fuer Festkoerperforschung Heisenbergstr 1 D 70569 Stuttgart Hahn Meitner Institut Glienicker Str 100 D 14109 Berlin Institut fuer Physik Universitaet Augsburg Memminger Str 6 and Universitaetsstr 1 D 86135 Augsburg KFK FK K ook ok ok K FK FK ok FK FK FK FK FK FK FK FK K K ok ok FK FK FK FK FK FK FK FK FK OK FK FK FK K FK FK K FK K K K KOK KK Version ASW 1 9 11 01 2002 Volker Eyert Copyright C 1992 2002 Volker Eyert General
8. 84 3 418 bnd tex dos tex 84 3 4 19 fre amp ps bnd ps dos ps coop p ei ar ee 84 main input file CTRL 87 Category 88 Category VERSION er hed 88 421 Token ASW 88 Category dot 6 hop Tel prb d 88 CONTENTS 4 4 4 5 4 6 4 7 ii 43d Token HELP e 222 522 242 212 Da a ed 89 4 3 2 Token SHOW 89 4 3 3 Token VERBOS nn 89 4 3 4 Token IACTIV 89 4 85 Token CLEANS uer ens das de ee m rer als 90 4 3 6 Token WRITE 90 At Token EXTEN S Sieira an che od ga A ee hes BS 90 Catepory OPTIONS see o E ON ee ren 90 Token REES he a ke doe 90 442 Token at a os aa Gela Ss 90 4 4 3 Token NSPIN 90 42 4 Toke AFSY YM bares 91 445 Token BEXT 91 ds Token c PADS usan 91 AAT oben GGA a Sane kod Gd cae 92 44 8 Token 92 4 4 9 Token CCOR 92 4 4 10 Token FULPOT 2 ra a IN dele ios eC RI ali i 92 4 411 Token CORDRD 92 Category STRUC mandatory
9. RR ERU EN ne Be 73 3 2 6 plbnd lx pldos ix pleop be 73 3 2 7 plbnd tex pldos tex plcop tex a 2 Pa 73 Installation shellscripts 73 Makefile a us ind ted ded a e ed Sem on 73 332 aut e 74 LS e ge le ooo a ni ar x hera 74 Be 74 README Sos nouis on E ot ee ee 74 INSTABLE x OR Sen 74 odo COPYRIGH I ead EROR EN ne Bed 74 IAA en eas ee 74 ad ME SIUE Te a BT a Ten 74 DD iE ds REGE en d 75 Ada V Aaa mE EEE dog Bb Say hs 75 DeL HELP axe Gd e SOR RO E A 75 3 4 9 The atomic files 82 fee MN 0 Te Vr d 83 var lan ee IZ hfe Et an d 83 Be 2 MEN aM OREME RUM xe oue de oS au 84 84 13 BNDE ae Sa EI EN a 84 od BND pind a eh ne ee 84 Bla DO a a a a Ts ae a Ts a 84 SIO a obs a GE he ee e aeu dead quatn ende 84 Jui QUE P A aub wie de UHR
10. 10 11 12 13 14 15 V Eyert Entwicklung und Implementation eines Full Potential ASW Verfahrens Ph D Thesis Technische Hochschule Darmstadt 1991 V Eyert J Comput Phys 124 271 1996 V Eyert Electronic structure calculations for crystalline materials in Den sity Functional Methods Applications Chemistry and Materials Science edited by M Springborg Wiley Chichester 1997 pp 233 304 V Eyert Octahedral Deformations Metal Insulator Transition in Transi tion Metal Chalcogenides Habilitation Thesis Universit t Augsburg 1998 V Eyert Basic notions and applications of the augmented spherical wave method Int J Quantum Chem 77 1007 1031 2000 V Eyert and K H H ck Phys Rev 57 12727 1998 J K bler and V Eyert Electronic structure calculations in Electronic and Magnetic Properties of Metals and Ceramics edited by K H J Buschow VCH Verlagsgesellschaft Weinheim 1992 pp 1 145 Volume 3A of Materials Science and Technology edited by R W Cahn P Haasen and E J Kramer VCH Verlagsgesellschaft Weinheim 1991 1996 J K bler K H H ck J Sticht and A R Williams J Phys F 18 469 1988 J K bler K H H ck J Sticht and A R Williams J Appl Phys 63 3482 1988 A R Williams J K bler and C D Gelatt Jr Phys Rev B 19 6094 1979 C D Gelatt Jr H Ehrenreich and R E Watson Phys Rev B 15
11. HEADER Cr02 rutile data by A A Bolzan C Fong B J Kennedy C J Howard Acta Cryst B53 373 1997 VERSION ASW 1 9 10 HELP F SHOW T VERBOS 30 CLEAN T OPTIONS REL T OVLCHK T STRUC ALAT 8 35618 SLAT ST CBYA 0 65958 CLASS ATOM CR Z 24 0 Z 8 SITE CARTP F ATOM CR 05 0 000000 0 000000 0 000000 ATOM CR 05 0 500000 0 500000 0 500000 0 POS 0 302400 0 302400 0 000000 0 POS 0 302400 0 302400 0 000000 ATOM 0 POS 0 197600 0 197600 0 500000 ATOM 0 POS 0 197600 0 197600 0 500000 SYMGRP ENVEL 0 015 BZSMP 6 0 0 BZINT SMS EMIN 1 0 EMAX 1 5 NDOS 1000 NORD 3 WIDTH 0 01 EFTOL 1 0D 04 SAVDOS F SAVCOOP F CONTROL START QUIT FREE F NITBND 99 CNVG 1 0D 08 CNVGET 1 0D 08 NITATM 50 CNVGQA 1 0D 10 MIXING NMIXB 5 0 5 INCBB T NMIXA 5 0 5 SYMLIN NPAN 10 NPTS 400 ORBWGT F CARTE F LABEL g ENDPT 0 0 0 0 0 0 LABEL X ENDPT 0 0 0 5 0 0 2 3 A MAGNETIC SYSTEM CRO 43 LABEL R ENDPT 0 0 0 5 0 5 LABEL Z ENDPT 0 0 0 0 0 5 LABEL g ENDPT 0 0 0 0 0 0 LABEL R ENDPT 0 0 0 5 0 5 LABEL A ENDPT 0 5 0 5 0 5 LABEL g ENDPT 0 0 0 0 0 0 LABEL M ENDPT 0 5 0 5 0 0 LABEL A ENDPT 0 5 0 5 0 5 LABEL Z ENDPT 0 0 0 0 0 5 PLOT CARTV F ORIGIN 0 0 0 0 0 0 RPLOT1 1 0 0 0 0 0 RPLOT2 0 0 1 0 0 0 RPLOT3 0 0 0 1 0 NPDIV1 50 NPDIV2 50 few new tokens are of special interest here Scoping with the tetragonal crystal structure we have inserted the token wh
12. 4 11 4 12 CONTENTS 4 7 5 Token POS 97 47 6 Tokens SPIN gow aed beh a eh 97 Category 97 4 81 Token 5 98 4 82 Token SYMOPS 98 4953 Token CARTR RS 99 Foken CU ET S decore ER mue xu S 99 Category b des bte d a mieu 99 49 1 Token 99 492 Token OBYDMX 99 4 9 3 Token OBYRMX 99 4 9 4 Token 100 4 9 5 Token NGEMAX 2 ue ch BAR 100 4 9 6 Token RADMIN 100 4 9 7 Token RADMAX 100 4 9 8 Token POTWIN 100 4 9 9 Token RADACC 101 4 9 10 Token POSACC us d dre Ste db dete doeet d eye Fe YS 101 Category BN YEA eto douce Rn e en mV ghe v 101 4 10 1 Token NKAP 101 1s Token EKAP wre a Be 101 Al od Toker EWPAR a p ea 101 4 10 4 Token EWTOL 102 Category 75 102 4 11 1 Token NKABC 4e ae m exl te Oe du ald 102 4 11 2 Token BZINT 3 eon 2 mn oo Ux Gv 102 4 11 3 Token EMIN
13. 8 CHAPTER 1 INTRODUCTION Here and in the following the term the author refers to Volker Eyert at the last of the above adresses You can contact the author via normal mail to the last of the above adresses or via email to eyertOphysik uni augsburg de Here and in the following the term ASW software package refers to the total of all files contained in the distribution in source and object form Here and in the following the term core of the ASW software package refers to the total of all files contained in the distribution in Source and object form except for those files which explicitly contain a copyright notice by other authors and except for the LAPACK and BLAS routines coming with the distribution FKK KK K K K FK K K FK K K FK K ook ok FK ck FK ck FK OK FK K FK FK K K FK 2K K KOK OK K Copyright notice The core of the ASW software package is copyrighted software It is not allowed to change any of the copyright notices in the core of the ASW software package It is not allowed to redistribute the core of the ASW software package or any part of it without prior written permission of the author It is not allowed to incorporate any part of the core of the ASW software package into any other software without prior written permission of the author It is illegal to commercially distribute the core of the ASW software package as a whole o
14. 4 4 4 Token AFSYM cast logical In spin polarized calculations this token allows to use spin sublattice symmetry which preserves the electronic states on going from one sublattice to the other and at the same time changing spins This symmetry allows to perform the band calculation for one spin only and to extract the other spins results from the first ones When AFSYM T is specified in addition for each atom the direction of spin has to be specified with the help of token SPIN see below A more detailed description of how to perform spin polarized calculations will be given in the respective section lateron 4 4 5 Token BEXT cast double This token comprises an external magnetic field in z direction The default value is BEXT 0 0 Note that use of finite magnetic fields has not yet been fully tested 4 4 6 Token XCPAR cast character Since version ASW 1 7 token XCPAR enables specification of different LDA schemes Actually almost all known parametrizations are included now The desired LDA parametrization is specified in the form XCPAR P S where P denotes the parametrization by KSG Kohn Sham and Gaspar exchange only GLW Gunnarsson Lundqvist and Wilkins JMW Janak Moruzzi and Williams VBH von Barth and Hedin MJW Moruzzi Janak and Williams PZ Perdew and Zunger VWN Vosko Wilk and Nusair PW Perdew and Wang and 5 denotes the spin interpolation by GLW Gunnarsson Lundqvist
15. 4794 076204 variational energy 4794 076245 qdiff 0 00000000 lt 0 00000001 ediff 0 00000000 0 00000001 ASW 1 9 program MNSCF ended on majestix at Sat 09 Mar 2002 17 35 06 According to this output a magnetic solution with a magnetic moment of 4 04g per unit cell has indeed been found Its stability becomes obvious from a comparison of the total energy to that of the non magnetic solution the difference being 24 mRyd per formula unit Worth mentioning is the considerable decrease of the DOS at Ep as compared to the non magnetic case In addition an indirect band gap of z 1 9 eV is obtained Taken together these findings confirm the half metallic of ferromagnetic behaviour of CrO as reported already by Schwarz This property is clearly visible in the band structure Fig 2 23 as well as in the corresponding E Eg eV Figure 2 23 Electronic bands of ferromagnetic CrO along selected symmetry lines within the first Brillouin zone of the simple tetragonal lattice Fig A 5 a density of states DOS as given in Fig 2 24 While the O 2p dominated spin up and spin down states still occupy similar energy intervals the Cr 3d bands experience spin splitting of about 2 eV As a consequence spin minority Cr 3d states are shifted above the Fermi energy and left unoccupied In contrast metallic conductivity is carried alone by the spin majority states As for the spin degenerate case the partial 58 CHAPTER 2 EXECUTION
16. In addition after having changed SAVDOS F to SAVDOS T as well as QUIT 14 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES to QUIT BND and running mnscf run again you will obtain a file DOS which holds all information about the partial densities of states for plotting The same can be achieved by invoking the shellscript mndos x which does the neccessary changes in the CTRL file and resets to the original state at the end and writes output to file outdos The previous calculations can be made automatic by typing mnall x This shell script performs a self consistent calculation for NKABC 6 0 0 this must be set the CTRL file then switches to NKABC 8 0 0 and then in several steps to NKABC 30 0 0 For each of these k point grids a self consistent calculation is performed Note that this saves a lot of execution time as compared to starting from scratch with a k point density of 30 This is due to the restart facility of the ASW program mnscf run Whenever the file checker in the program detects atomic files which conform with the general settings of the CTRL file as e g the lattice type or the number and types of orbitals the program is able to use this information as a starting point for further calculations In particular once the calculations for NKABC 6 0 0 have converged the subsequent calculation for NKABC 8 0 0 starts out from the converged files rather than starting from scratch As a result only few iterations wil
17. QSUB 1M 256MB Specify start from the current working directory if QSUB_WORKDIR 1 then cd QSUB WORKDIR fi Specify stdout and stderr QSUB job out QSUB e job err Specify shell 0SUB s bin bash Mark the job not restartable QSUB nr Require mailing at job starting and ending time QSUB mb QSUB me 66 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE Portable Batch System PBS specifications Specify job queue PBS q dft Specify system and hardware requirements PBS 1 resc arch solaris arch irix Specify requirements for parallel execution PBS 1 nodes 1 Specify CPU time and memory PBS 1 cput 168 00 00 PBS 1 mem 256MB Specify start from the current working directory if PBS_O_WORKDIR 1 then cd PBS_O_WORKDIR fi Specify stdout and stderr PBS job out PBS e job err Specify the shell PBS S bin bash Export all environmental variables PBS V Mark the job not restartable PBS rn Suppress any notification PBS m n
18. 0 411732 20 218838 0 355939 SPIN DN 05 0 281162 0 088268 0 144061 SPIN UP P08 0 281162 0 088268 0 144061 SPIN UP 05 0 411732 20 218838 0 355939 SPIN DN 05 0 411732 0 218838 0 355939 SPIN DN 05 0 218838 0 411732 0 355939 SPIN DN 05 0 218838 0 411732 20 355939 SPIN DN 05 0 088268 0 281162 20 144061 SPIN UP P08 0 088268 0 281162 0 144061 SPIN UP P08 0 088268 0 281162 20 144061 SPIN UP 05 0 088268 0 281162 0 144061 SPIN UP 0 0 302400 0 000000 SPIN UP 0 0 0 Note that for each class there must be an equal number of SPIN UP and SPIN DN entries Again the self consistent calculation is started by typing mnall x 60 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES at the systems prompt In case you have forgotten to copy the atomic files of the ferromagnetic calculation the program will start from scratch and hence need more iterations Of course for antiferromagnetic materials it is not not necessary to perform a ferromagnetic calculation first You could also use the atomic files of a spin degenerate calculation as a starting point for an antiferromagnetic calculation After convergence susan outlst30 summarizes the results as follows ASW 1 9 program MNSCF started on majestix at Wed 13 Mar 2002 08 30 07 Calculation converged after iteratio
19. 1613 1977 L Hodges R E Watson H Ehrenreich Phys Rev B 5 3953 1972 R E Watson H Ehrenreich and L Hodges Phys Rev Lett 15 829 1970 O K Andersen Phys Rev B 12 3060 1975 M S Methfessel and A T Paxton Phys Rev B 40 3616 1989 125 126 16 17 18 19 20 21 22 23 24 25 26 21 BIBLIOGRAPHY V L Moruzzi J F Janak and R Williams Calculated Electronic Prop erties of Metals Pergamon Press New York 1978 G A Burdick Phys Rev 129 138 1963 R Hoffmann Solids and Surfaces A Chemist s View of Bonding in Extended Structures VCH New York 1988 V Eyert and S F Matar unpublished results 1995 V Eyert B Siberchicot and M Verdaguer Phys Rev B 56 8959 1997 N B rnsen B Meyer O Grotheer and M F hnle J Phys Cond Matt 11 L287 1999 Th Straub R Claessen P Steiner S H fner V Eyert K Friemelt and E Bucher Phys Rev B 55 13473 13478 1997 V Eyert K H H ck S Fiechter and H Tributsch Phys Rev B 57 6350 1998 K Schwarz J Phys F16 L211 1986 S Matar G Demazeau J Sticht V Eyert and J K bler J Phys I France 2 315 1992 J Phys I France 4 1259 1994 S Matar V Eyert J Sticht J K bler and Demazeau J Phys I France 4 1199 1994 A A Bolzan C Fong B J Kennedy and C J Howard Acta Cryst B 53 373 1997
20. By now you are in a position to invoke the plotting routines Just type plbnd run and enter the following dialog ASW 1 9 program PLBND started on majestix at Fri 08 Mar 2002 18 02 21 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details All input will be echoed to file PLIB Enter terminal type 1 X Windows default 2 PC Screen vt220 emulation 3 suppress terminal output Enter output device 1 Postscript default 2 Color postscript 3 LaTeX 4 LaTeX VE s way 5 HP LaserJet III PCL5 6 HP LaserJet II 7 GIF 8 leave the decision for later 9 suppress output to file Enter title Energies in Rydberg f or eV t default Energies relative to MTZ 0 or EFermi F default Portrait P default landscape L or encapsulated postscript plot E Energies connected by lines t default f Please wait a moment I m reading the bands Timing for 39 points out of 398 0 00000 sec Ebot Emin 7 Enter new Emin Emax to change these defaults task 1 total cpu time 0 01000 sec 9 643162 eV Etop 10 000000 eV Emax 28 337884 eV relative to EF 6 000000 eV relative to EF ASW 1 9 program PLBND ended on majestix at Fri 08 Mar 2002 18 02 21 Here entered on the programs prompt will keep the default values proposed by the program the questions are self explaining After this dialog new files have been created as there
21. RPLOT3 of cast double and length 3 3 4 DATA FILES 8l Plot vector specifying plot space token NPDIVi of cast integer Number of divisions of plot space token NPDIV2 of cast integer Number of divisions of plot space token NPDIV3 of cast integer Number of divisions of plot space In addition an output file is generated which includes a full CTRL file where all categories and tokens are given with their default values This output looks like ASW 1 9 program MNSCF started on majestix at Wed 13 Mar 2002 08 38 28 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details Write information to file HELP for HELP T SHOW T lists default values for optional input Echo CTRL file for SHOW T HEADER VERSION ASW 1 9 IO OPTIONS STRUC CLASS SITE SYMGRP PACK ENVEL BZSMP CONTROL MIXING SUPCELL SYMLIN HELP T SHOW T VERBOS 30 IACTIV F CLEAN T WRITE CBAK EXTENS REL T LSCPL F NSPIN 1 AFSYM F BEXT 0 0 XCPAR VWN VWN GGA OVLCHK T CCOR T FULPOT F CORDRD F UNITS BOHR ALAT 0 0 PLAT 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SLAT BBYA 1 0 BLAT 0 0 CBYA 1 0 CLAT 0 0 GAMMA 90 0 NCLASS 1 ATOM Z 0 R 0 0 R RA 1 0 LMXL 2 LMXI 3 CONF 1 2 3 4 QVAL 0 0 0 0 0 0 0 0 MVAL 0 0 0 0 0 0 0 0 NBAS 1 CARTP T CHOUT F ATOM 05 0 0 0 0 0 0 SPIN UP GENPOS F SYMOPS CARTR T CARTT T FILLNG 1 0 OBYDMX 0 15 OBYRMX 0 4 ESBONS 0 05 RADMIN 0 5 RADMAX 5 0 POTWIN 0 0 RADACC 1 0D 02 POSACC 1 0D 03
22. all 1 all p 2 alld 1 s 2 y 3 2 4 x 5 6 2 T 3z 2 r 2 8 2 9 x 2 y 2 Class 0 atom 6 at 0 197600 0 197600 0 329790 Select from the following orbitals 0 all 1 all p 2 alld 1 s 2 y 3 2 4 x 50 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES 6 yz 7 3z 2 r 2 8 2 Select from the classes blank or to complet CR 0 E1 E2 The following orbitals have been selected Class 0 atom 3 orbital y Class 0 atom 3 orbital z Class 0 atom 3 orbital x Class 0 atom 4 orbital y Class 0 atom 4 orbital 2 Class 0 atom 4 orbital x For this choice of orbitals rotation of the refe Enter scaling factor default 1 0 Broadening of this curve t or not f default Select curve style default 3 A marks style solid green 1 dashedi blue dashed2 red 3 dotted magenta dashdottedi cyan 5 dashdotted2 yellow chaindashed1 black 7 chaindashed2 coral chaindashed3 gray 9 Enter curve label to suppress 0 2p Please wait a moment I m working on this curve Set up more curves t Default is f Center of gravity of DOS curve 1 Spin 1 Center of gravity of DOS curve 2 Spin 1 Center of gravity of 005 curve 3 Spin 1 EF Indicate center of gravities f default Ebot 19 827771 Etop 10 172793 eV Emin 20 000000 eV Emax 6 000000 eV Enter new Emin Emax to change these def
23. 1 this diversity shows up mainly in the 3d series which comprises the large gap Table 2 1 Properties of transition metal dioxides with rutile related structure um d d d d 3d TiO CrO MnO S M S 5 4 NbOj 0 TcOj Ru M S wo ReO3 PtOj 7 deviations from rutile M metal S semiconductor F AF ferro antiferromagnet semiconductor TiO the metal insulator system the half metallic ferromag net CrOg and the antiferromagnetic semiconductor MnO 3 In contrast except for which like undergoes a metal insulator transition accompanied by a structural transition the 4d and 5d compounds are neither semiconducting nor magnetic Nevertheless there exist several members in each group which display small but characteristic deviations from the rutile structure 4 The electronic structure of has been under discussion for a long time The first calculation performed by Schwarz using the ASW method revealed CrO as a half metallic ferromagnet where spin majority electrons carry metallic conductiv ity while the spin minority bands show a gap at the Fermi energy 24 Subsequent 2 3 A MAGNETIC SYSTEM CRO 41 calculations by Matar and coworkers confirmed these findings and revealed the insta bility of the compound towards antiferromagnetism on slight changes of the
24. 2 1 The following orbitals have been selected Class CU atom 1 orbital y Class CU atom 1 orbitalz Class CU atom 1 orbital x Enter scaling factor default 1 0 Broadening of this curve t or not f default Select curve style default solid green 1 dashedi blue 2 dashed2 red 3 dotted magenta 4 dashdottedi cyan 5 dashdotted2 yellow 6 chaindashedi black 7 chaindashed2 coral 8 5 chaindashed3 gray 9 Enter curve label to suppress 2 A marks styles already selected 2 1 SIMPLE CASE CU Cu 4p Please wait a moment I m working on this curve Set up more curves t Default is f t Start setting up curve 3 Plot partial f or total DOS t default For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default E Enter orbital s to be included Class CU atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 allp 2 alld 3 all f 1 s 2 y 3 2 4 x 5 6 yz 7 3z 2 r 2 8 2 9 x 2 y 2 10 11 xyz 12 5yz 2 yr 2 13 5273 32 72 14 5xz 2 xr 2 15 16 x 3 3xy 2 5 6 8 The following orbitals have been selected Class CU atom 1 orbital xy Class CU atom 1 orbital yz Class CU atom 1 orbital xz Enter scaling factor default 1 0 Broadening of this curve t or not f default Select curve style default solid green 1 dashed
25. 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES dashed2 red 3 dashdottedi cyan 5 chaindashedi black 7 dotted magenta 4 dashdotted2 yellow 6 chaindashed2 coral 8 gt chaindashed3 gray 9 Enter curve label to Cr 3d t_ 2g suppress Please wait a moment I m working on this curve Set up more curves t Default is f T Start setting up curve 2 Plot partial f or total DOS t default F For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default R8 1 1 0 R4 1 1 0 Enter orbital s to be included Note notation of the orbitals refers to the rotated reference frame Select from the classes blank or to complete the list CR 0 1 2 CR Class CR atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 3 all 158 2 3 2 4 x 6 2 7 3z 2 r 2 8 2 9 x 2 y 2 10 3x 2y y 3 11 2 12 5yz 2 yr 2 13 5273 32 72 14 5xz 2 xr 2 15 x 2z y 2z 16 x 3 3xy 2 5 7 Class CR atom 2 at 0 500000 0 500000 0 329790 Select from the following orbitals 0 all 1 all p 2 alld 3 all f 1 s 2 y 3 2 4 x 6 2 7 3z 2 r 2 8 2 9 x 2 y 2 10 3x 2y y 3 11 2 12 5yz 2 yr 2 13 5273 32 72 14 5xz 2 xr 2 15 x 2z y 2z 16 x 3 3xy 2 Select from the classes blank or to complete the list CR 0 1 2 The following orbitals have been se
26. 210048 210048 210048 110792 110792 242766 242766 257234 257234 257234 257234 096691 096691 0 0 369247 50 096691 096691 242766 242766 130753 130753 403309 403309 403309 403309 369247 369247 461787 461787 130753 130753 369247 115160 384840 115160 384840 115160 110792 110792 110792 110792 389208 389208 205225 205225 210048 210048 289952 289952 294775 294775 389208 389208 289952 289952 205225 205225 294775 294775 210048 210048 369247 369247 369247 369247 130753 130753 257234 257234 403309 403309 096691 096691 242766 242766 130753 130753 096691 096691 257234 257234 242766 242766 403309 403309 344830 344830 35 36 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES ATOM E3 POS 0 282017 0 038213 0 344830 POS 0 282017 0 038213 0 344830 ATOM E3 POS 0 217983 0 038213 0 155170 ATOM E3 POS 0 217983 0 038213 0 155170 ATOM E3 POS 0 344830 0 282017 0 038213 ATOM E3 POS 0 344830 0 282017 0 038213 ATOM E3 POS 0 038213 0 155170 0 217983 ATOM E3 POS 0 038213 0 155170 0 217983 ATOM E3 POS 0 038213 0 344830 0 282017 ATOM E3 POS 0 038213 0 344830 0 282017 ATOM E3 POS 0 155170 0 282017 0 461787 ATOM E3 POS 0 155170 0 282017 0 461787 ATOM E3 POS 0 282017 0 461787 0 155170 ATOM E3 POS 0 282017 0 461787 0 155170 ATOM E3 POS 0 461787 0 155170 0
27. 643162 eV Etop 28 337884 eV relative to EF Emin 10 000000 eV Emax 6 000000 eV relative to EF Enter new Emin Emax to change these defaults Rescale orbital weights default 0 4000eV 2 Please wait a moment I m working on the weights Timing for 19 points out of 199 0 00000 sec Enter the horizontal and vertical extension in mm Default 100 0x 90 0 task 1 total cpu time 0 04000 sec ASW 1 9 program PLBND ended on majestix at Fri 08 Mar 2002 21 26 15 It differs from the above dialog in asking for Plot orbital character default f and the particular orbital s to be included This section is similar to the plotting of the partial DOS above The previous dialog will produce a file bnd ter which can be converted into bnd ps by typing plbnd lx at the system prompt The result is shown in Fig 2 3 In a similar way orbital weighted band structures for the 4p and 3de states can be obtained They are shown in Figs 2 4 2 5 and 2 6 In all these figures we recognize the same band structure as already given in Fig 2 1 Yet in Figs 2 3 to 2 6 to each band at each k point has been appended a bar length of each bar is a measure of the contribution of a particular orbital to the respective wavefunction be specific we identify large 4s and 4p contributions at the bottom as well as at the high energy branches of the parabola starting at 9 64 eV In contrast the 3d orbitals dominate in the en
28. 71 6 In addition the following short hand notations exist While D is short for the diagonal i e the vector 1 1 1 X Y and 77 abbreviate the vectors 1 0 0 0 1 0 and 0 0 1 The following examples will help understanding this notation R6 1 0 0 a positive rotation by 60 about the x axis R6 1 0 0 a positive rotation by 60 about the x axis i e a negative rotation by 60 about the x axis R6 C S 0 a positive rotation by 60 about the axis 0 5 0 8660 0 R3D a positive rotation by 120 about the 1 1 1 axis RA 1 1 0 T 0 0 0 5 a positive rotation by 90 about the 1 1 0 axis followed by a translation by the vector 0 0 0 5 MX a reflection about the plane spanned by the y and z axis which transforms x to x I the inversion The operations RAX MX and R3D are sufficient to generate all 48 elements of the full cubic group Finally all the aforementioned operations may be combined by where A B is converted to mat A mat B i e the operations are applied from right to left Note the originally 4x4 character of all operations when combining them 499 CATEGORY PACK 99 4 8 3 Token CARTR cast logical This switch specifies whether the entries for the rotation axes are interpreted as Cartesian coordinates CARTR T or as relative components in terms of the prim itive translations CARTR F The default value is CARTR T 4 8 4 Token CARTT cast logical This switch specifies whether the
29. ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 05 0 115160 384840 POS 0 384840 210048 05 0 05 0 05 0 05 0 05 0 289952 POS 0 210048 210048 05 0 05 0 05 0 05 0 POS 0 205225 205225 205225 205225 389208 389208 289952 289952 294775 294775 389208 389208 05 0 POS 0 POS 0 05 0 05 0 POS 0 POS 0 05 0 05 0 05 0 05 0 05 0 POS 0 05 0 294775 294775 403309 403309 05 0 05 0 05 0 05 0 05 0 096691 403309 05 0 05 0 05 0 369247 POS 0 05 0 257234 257234 POS 0 257234 05 0 05 0 096691 05 0 05 0 05 0 POS 0 05 0 242766 242766 05 0 POS 0 05 0 369247 05 0 POS 0 05 0 POS 0 242766 217983 217983 05 0 05 0 POS 0 115160 115160 210048 289952 110792 110792 110792 110792 096691 403309 369247 257234 130753 130753 096691 130753 130753 369247 242766 0 384840 115160 115160 115160 115160 294775 294775 205225 205225 205225 205225 289952 289952 389208 389208 110792 110792 289952 289952 294775 294775 389208 389208 210048
30. V0 2P207id Whenever you want to perform a calculation for one of the systems already in the database just copy the CTRL file However please read the README file contained in the database before In turn I do welcome any new CTRL file 120 CHAPTER 5 THE ASW DATABASE Appendix Brillouin zones This Appendix displays the Brillouin zones of some lattices a P 3 en LAN fl ky X ky k simple cubic b T structure c face centered cubic d body centered cubic Figure A 1 Brillouin zones of cubic lattices 121 122 APPENDIX BRILLOUIN ZONES kz Ms z Z ar hey i a simple tetragonal b centered tetragonal Figure A 2 Brillouin zones of tetragonal lattices kz ys X End po t R T ky r mr gt ky E _ _ Pd SN xum a simple orthorhombic b base centered orthorhombic Figure A 3 Brillouin zones of orthorhombic lattices Figure A 4 Brillouin zones of hexagonal lattice 123 simple tetragonal b simple monoclinic Figure A 5 Brillouin zones of rutile and related structures 124 APPENDIX BRILLOUIN ZONES Bibliography
31. and Wilkins VBH von Barth and Hedin VWN Vosko Wilk and Nusair PW Perdew and Wang Note that while the default was XCPAR MJW VBH in all versions up to ASW 1 6 it is now set to the more accurate XCPAR VWN VWN 92 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 4 7 Token cast character In version ASW 1 8 a new token GGA has been included which allows specifica tion of different schemes of the generalized gradient approximation GGA Possible parametrizations are GGA G where G denotes the parametrization by PW Perdew and Wang 1991 GGA I EV Engel and Vosko 1993 PBE Perdew Burke and Ernzerhof 1996 The default is GGA which means to use none of these schemes 4 4 8 Token OVLCHK cast logical In elder versions of the standard ASW method and also the LMTO method slight ambiguities came in by bad settings of the atomic sphere radii Most of such inaccu racies come from too large overlap of the spheres In particular for the ASW method the situation has much improved by the invention of the sphere geometry optimiza tion SGO algorthim which allows to automatically evaluate the radii However it is still recommended to check the radii for too large overlap This overlap check is invoked by the token OVLCHK which by default is OVLCHK T 4 4 9 Token CCOR cast logical This switch enforces use of the socalled combined correction to the ASA Actually the term combined correction is more rel
32. are BND GNU BND1 and BOX By typing gnuplot BND GNU you will invoke gnuplot and obtain the plot on screen In addition a postscript file bnd ps is created also containing the plot For Cu the result is shown 16 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES in Fig 2 1 As we will discuss in more detail below the band structure comprises E Eg eV W L X W K Figure 2 1 Electronic structure of Cu along selected symmetry lines of the first Brillouin zone of the face centered cubic lattice see 1 a parabolic band starting at the at about 9 64 eV and ending near the W point at 6 eV This s like band hybridizes with the five d bands which are visible in the energy interval from 5 5 to 1 5 eV Note the degeneracies of the d bands especially along the lines T L and Still the procedure can be simplified by calling the shellscript plbnd x rather than typing plbnd run This will run the plot program and invoke Gnuplot automatically Moreover the intermediate files BND GNU BND1 and BOX will be deleted by the shellscript However user friendlyness goes even beyond During execution the plot routine plbnd run has echoed all your input to new file called PLIB By inspecting this file you will find a fully commented echo of all your input Rename this file to e g PLIBf type plbnd x PLIBf and you obtain the same result as before without having to type anything else This machinery could now be use
33. case just enter f in the dialog 3 2 4 pldos run pldos x The plot program pldos x enables plotting of the total and partial densities of states DOS Both the DOS itself and the integrated DOS can be displayed Input is read from file DOS Intermediate files are prepared for both Gnuplot and however for the DOS Gnuplot produces a nicer output usually contained in the postscript file dos ps During the dialog the user is asked for the energy window scale and reference In addition for each curve the orbitals to be included and a scaling factor must be specified Finally the curve can be broadened by folding with a Gaussian or a Lorentzian The number of curves is limited to nine by the porgram Finally as for plotting the band structure a rotation matrix can be specified for each curve in order to make the program refer the orbitals to a rotated coordinate system 3 2 5 plcop run plcop x This program must be used for plotting the total and partial crystal orbital overlap population COOP Again also the integrated quantities can be plotted Input is read from file COOP If Gnuplot is specified for output usually a file coop ps The dialog proceeds in much the same way as for pldos x However note that for each curve two orbitals have to given Again Gaussian or Lorentzian smearing can be used 3 2 6 plbnd lx pldos lx plcop ix These shellscript include files bnd tex dos tex and coop tex into K TEXenvelop
34. complicated structure While the calculations for Cu didn t even allow for a coffee break we next turn to a more complicated case with an increased demand of computer resources To be specific we turn to the case of iron pyrite FeS2 which is the prototype member of a whole class of transition metal disulfides Background information about this compound is given in Ref 23 Due to the increased complexity of the crystal structure we will use additional programs coming with the ASW pacakge 2 2 1 CTRL file and sphere packing pyrite structure is based on a simple cubic lattice with iron atoms located at the corner of the cell and sulfur pairs aligned along the spave diagonal This information is contained in the following CTRL file HEADER FeS2 sc data by E D Stevens M L DeLucia and P Coppens Inorg Chem 19 813 1980 VERSION ASW 2 0 IO HELP F SHOW T VERBOS 30 CLEAN T OPTIONS REL T OVLCHK T STRUC 10 23476 SLAT SC CLASS 2 26 ATOM S 27 16 SITE CARTP T ATOM FE POS 0 000000 0 000000 0 000000 ATOM FE POS 0 000000 0 500000 0 500000 ATOM FE POS 0 500000 0 000000 0 500000 ATOM FE POS 0 500000 0 500000 0 000000 ATOM S POS 0 384840 0 384840 0 384840 ATOM S POS 0 115160 0 384840 0 115160 ATOM S P08 0 384840 0 384840 0 384840 ATOM S POS 0 115160 0 384840 0 115160 ATOM S POS 0 115160 0 115160 0 384840 ATOM S 05 0 384840 0 115160 0 115160 ATOM S POS 0 115160 0 115160 0 384840 A
35. crystal structure as might be caused by the fabrication of thin films 25 26 Since then several workers have dealt with the material in order to explain the ferromagnetic order The rutile structure of CrO is based on a simple tetragonal lattice with space group P45 mnm Dit No 136 and lattice constants a 4 4219 2 9166 27 The metal atoms are located at the Wyckoff positions 2 0 0 0 5 5 5 and the oxygen atoms occupy the positions 4f u 0 2 u 1 u 5 with u 0 3024 The rutile structure is displayed in Fig 2 15 The structure can be Figure 2 15 The rutile structure Large and small spheres denote metal and ligand atoms respectively alternatively visualized in terms of a body centered tetragonal lattice formed by the metal atoms where each metal atom is surrounded by an oxygen octahedron Octahedra centered at the corners and the center of the cell are rotated by 90 about the tetragonal c axis relative to each other As a consequence the lattice translational symmetry reduces to simple tetragonal and a unit cell with two formula units results Octahedra which are neighboured along the rutile c axis share edges whereas the resulting octahedral chains are interlinked via corners Each octahedron 42 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES has orthorhombic symmetry although the deviations from tetragonal and even cubic geometry for most compounds are relatively small and stil
36. d 2_ 2 orbital the result is shown in Fig 2 20 It resulted from calling the plot program plbnd x and entering the following dialog ASW 1 9 program PLBND started on majestix at Thu 14 Mar 2002 15 54 09 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details All input will be echoed to file PLIB 2 3 A MAGNETIC SYSTEM 2 53 bo d T S T 1 0 0 5 1 0 RZ RA 7 Figure 2 20 Weighted electronic bands of CrO The width of the bars given for each band indicates the contribution due to the 3d 2_ 2 orbital of the Cr atom at 0 0 0 relative to the local rotated reference frame Enter terminal type 1 X Windows default 2 PC Screen vt220 emulation 3 suppress terminal output Enter output device Postscript default Color postscript LaTeX LaTeX VE s way HP LaserJet III PCL5 HP LaserJet II GIF leave the decision for later suppress output to file 4 Enter title Energies in Rydberg f or eV t default Energies relative to MTZ 0 or EFermi F default Portrait P default or landscape plot L Energies connected by lines t default f Plot orbital character default f T For plotting orbital character Rotate reference frame for orbitals 54 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES Ente
37. distributed under the name Electra for Electronic Structure and Analysis by Materials Design Inc Angel Fire NM and Materials Design s a r l Le Mans See http www materialsdesign com for more information Any questions criticisms and suggestions concerning the ASW program package or this manual are welcome Please feel free to contact me via email to eyert physik uni augsburg de This user guide falls into three parts Following this introductory chapter the ca pabilities of the program package are demonstrated by three examples in Chap 2 Chap 3 comprises an overview over all programs shellscript and data files coming with the distribution or being created during execution A detailed discussion of the main input file of the package the CTRL file is finally given in Chap 4 While the more experienced practioner will use this chapter as a reference beginners are strongly recommended to work through the examples of Chap 2 first 1 2 Physical background As many other ab initio approaches the ASW method is based on the Born Oppen heimer approximation which allows to consider the electronic structure independent of the lattice dynamics Furthermore it makes use of crystalline periodicity and the Bloch theorem built thereon Finally the ASW method relies on density functional theory DFT as founded by Hohenberg Kohn and Sham 1 2 PHYSICAL BACKGROUND 3 As it stands the ASW program package employs the local
38. distribution or are meant for information exchange between different programs Neither of these latter files has to be changed by the user Anyway in the following list a short description is given for all files 3 4 1 README The README comprises a shortcut version of this user guide Actually the present manuscript has its roots in the README file It contains very brief information about the distribution installation and execution of the programs as well as some remarks about external software to be used with the ASW program package 3 4 2 INSTALL A concise description of the installation process is provided by this file 3 4 3 COPYRIGHT The COPYRIGHT file covers all the copyright information concerning the ASW program package It is printed in Sec 1 6 and should be read by any user at the very beginning 3 4 4 LICENCE The LICENCE file contains a single line indicating the expiration date for the present licence 3 4 5 CTRL The CTRL file is the one and only input file to the main programs It e is fully free format and thus allows for a flexible setup 3 4 DATA FILES 5 is subdivided in sections categories each containing a set of catchwords tokens e has many options e many useful defaults The CTRL file contains information about e the crystal structure e the constituent atoms e the symmetry lines e settings for input output e parameters for sphere packing e Brillouin zone sampling e iterat
39. potential version which will be soon available As an all electron scheme the ASW method fully includes both the core and the valence electrons in the self consistent field calculations For this reason it allows full coverage of the periodic table including transition metal atoms as well as the lanthanides and actinides The codes is applicable to metal semiconductors and insulators without any restrictions Much of the efficiency of the program package stems from the use of a minimal basis set built from atomiclike s p d orbitals As a consequence each atom contributes with nine or 16 basis functions to the secular matrix which is much less than the 100 functions necessary in plane wave based methods Furthermore the atomiclike orbitals allow for an easy setup of e g partial densities of states and a much more natural interpretation of the results Additional speedup of the program results from the fact that the ASW method like the LMTO or LAPW is a socalled linearized method The latter approach as invented by Andersen is based on the observation that the energy dependence of the wave function is rather weak and hence may be well approximated by only few terms of a Taylor expansion Within the ASA only the first two terms are actually needed the famous and of the LMTO method As a result solving for the zeros of the secular matrix reduces to an eigenvalues problem which is tractable by standard routines and can thus be done
40. programs At the present stage you may just construct a CTRL file like VERSION ASW 1 8 IO HELP T and run an ASW program For most of the tokens listed below there exist default values which have been thoroughly tested and tuned to optimal performance For this reason only very few information is actually needed to successfully run the ASW program This includes atomic numbers and crystal structure data as lattice constants and atomic positions The respective categories and tokens are indicated as mandatory below 4 1 Category HEADER This category is meant to hold a short description of the calculation At present this category is limited to 20 lines Formally the first line is treated differently from the following lines as it is interpreted as a title which by default is appended to most plots For this reason I recommend to specify only a short title in the first line and to put longer comments into the following lines Usually I include references to important previous work on this compound in these lines 4 2 Category VERSION This category contains information about the version of the ASW package which you are currently working with 4 2 1 Token ASW cast real This token specifies the version and release number of the ASW program you are intending to work with It consists of two one digit numbers separated by a dot For the present version the default is ASW 1 9 This token is useful if you want to use a CTRL file wr
41. scheme used for the Brillouin zone in tegration At present it can be either BZINT SMS simple sampling which is the default or BZINT HPS high precision sampling The former scheme uses a simple histogram technique For this reason it is highly efficient however due to its statistical nature the calculated densities of states look rather noisy Still this scheme is a very good choice as long as energy integrated quantities are aimed at as is the case during the iterations to self consistency After full self consistency is achieved it is recommended to use the high precision sampling as proposed by 4 11 CATEGORY BZSMP 103 Methfessel and Paxton 15 which produces very nice results Future versions of the program will also include the linear tetrahedron method choosen by BZINT LTM 4 11 3 Token EMIN cast double The tokens EMIN and EMAX fix the energy interval used for the calculation of the partial densities of states Note that this interval is used not only for visualization purposes but also during the iterations towards self consistency where the ntegrated DOS is needed for calculating the electronic charge density For this reason EMIN and EMAX must be below the lowest valence band and higher than the Fermi energy respectively The default value is EMIN 2 0 Ryd 4 11 4 Token EMAX cast double Token EMAX fixes the upper bound of the interval used for the densities of states calculation It must be above the Fermi
42. switch specifies whether the following entries for the end points of the sym metry lines are interpreted as Cartesian coordinates CARTE T or as relative components in terms of the primitive translations CARTE F The default value is CARTE T 112 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 15 5 Token LABEL cast character There exists standard notation for labelling the high symmetry points of the first Brillouin zone These labels are usually appended to the band structure plots 4 15 6 Token ENDPT cast double length 3 This token holds the end points of the symmetry lines along which the band struc ture should be plotted 4 16 Category PLOT The last category contains information to be used for 3D plots of e g the crystal structure the charge density or the potential This comprises a set of vectors con fining the plot space a line a plane or a volume as well as the divisions along these vectors 4 16 1 Token CARTV cast logical This switch specifies whether the following entries for the plot vectors are interpreted as Cartesian coordinates CARTV T or as relative components in terms of the primitive translations CARTV F The default value is CARTV T 4 16 2 Token ORIGIN cast double length 3 This token is useful if the origin of the plotting volume deviates from the origin of the unit cell as specified by token PLAT in category STRUC Default is ORIGIN 0 0 0 0 0 0 4 16 3 Token RPLOTI cast double len
43. the eigenvectors are written to the unformatted file BNDV by program mnbnd run 3 4 15 DOS The unformatted file DOS is written by program mnscf run if token SAVDOS T is set It contains the partial DOS for later plotting 3 4 16 For SAVCOOP T and the respective settings COORB program mnscf run creates an unformatted file COOP which holds all information about the partial crystal orbital overlap populations COOP the crystal orbital Hamiltonian population or the covalence energy 3 4 17 out Naming of the output files is completely free However if you are using the shell scripts mn x output is written to file out where the last three letters indicate the type of the program In contrast shellscript mnall x writes output files outlstnn where nn ranges from 6 to 30 according to the k space grid 3 4 18 bnd tex dos tex coop tex These IXTEXfiles are created by the plot programs plbnd run pldos run and plcop run respectively if TEXoutput has been specified in the dialog 3 4 19 free ps bnd ps dos ps coop ps postscript files created by the plot programs 3 4 DATA FILES 85 These postscript files are created by the plot programs plfre run plbnd run pl dos run and plcop run respectively if Gnuplot postscript output has been specified in the dialog 86 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE Chapter 4 The main input file CTRL In this chapter we describe
44. the overlap check for the atomic spheres QUIT REN Program mnscf run stops after having finished a free atom calcula tion QUIT ATM Program mnscf run stops after having finished the intraatomic atom calculations for the first time QUIT BND Program mnscf run stops after having finished the band calculations for the first time QUIT DOS Program mnscf run stops after having finished the band calculations for the first time but before calculating new moments of the partial densities of states This setting is particularly useful for calculating the partial densities of states in a single run after self consistency has been achieved 4 12 3 Token FREE cast logical This token has two different meanings The default is FREE F First if program mnscf run is called with FREE T is performs a free atom calculation for all atoms in the unit cell Second if used with program mnbnd run FREE T enforces calcu lation of the free electron bands 4 12 4 Token NITBND cast integer This token fixes the maximum number of iterations to be done by the program The default value is NITBND 20 This token is useful if only a limited amount of CPU time is available good estimate for the total execution time can be evaluated as follows For most applications the band part of the calculations takes about 9596 of the total execution time Once the band calculation i e the loop over all k points has started the program checks the CPU time per k p
45. to new intraatomic wave functions and matrix elements for use in the band part However the effective potential could be likewise used to construct via the wave functions a new charge density This gives rise to an iteration to wards full intraatomic convergence within the limits set by the partial charges and logarithmic derivatives as grown out of the previous band part Only after this self consistency cycle has converged new wave functions and matrix elements for the subsequent band part are supplied Note that during the intraatomic calculations the atomic files are accessed several times Stopping the program in this step thus might cause a loss of files 3 1 9 mndos x During normal execution of program mnscf run only resolved partial densities are usually calculated This saves both execution time and memory Once the itera tions have converged the shellscript mndos x will call the program mnscf run once more If present before tokens SAVDOS F and SAVCOOP F will be changed to SAVDOS T and SAVCOOP T respectively BZINT SMS is set to BZINT HPS and NKABC 6 is changed to NKABC 30 After the band part has been finished and the partial DOS and COOPs are written to files DOS and COOP the porgram stops and the above changes of the CTRL file are reset to their original values 3 1 10 mnbnd run mnbnd x Another quantity of interest after full convergence has been achieved is the band structure It is calculated by employing the shellscript
46. versa By setting CHOUT T you may enforce that the respective other represnetation is written to the backup copy of the CTRL file see token WRITE above The default is CHOUT F 4 7 4 Token ATOM mandatory cast character Before entering the atomic positions you must for each site give the class label in order to attach entries in categories CLASS and SITE to each other Hence the present token must match one of the ATOM entries given in category CLASS 4 7 5 Token POS mandatory cast double length 3 Here you must specify the atomic position in the representation selected by the above token CARTP 4 7 6 Token SPIN cast character In case of antiferromagnetic order the site information may be complemented with information about the sublattice spin up or down the respective atom belongs to This can be done by setting SPIN UP or SPIN DN for each atom Obviously the number of UP and DN entries must be equal for each class Note that these entries are used only if AFSYM T is given in category OPTIONS 4 8 Category SYMGRP Information about the analysis and use of space group symmetry underlying the crystal structure is supplied by this category There exist essentially two modes Either the symmetry of the crystal may be analyzed from the above information about the atomic classes and sites This is the default However for large systems 98 CHAPTER 4 THE MAIN INPUT FILE CTRL it may be useful to enter only minimal s
47. warn for the missing classes and stop The default is NCLASS 1 4 6 2 Token ATOM mandatory cast character Here you must label each of the classes In the course of the calculations these labels are used to name the atomic files My personal preference is to label classes by their names given in the periodic table extended by a roman number whenever different classes with the same atomic number exist 4 6 3 Token Z mandatory cast integer This entry holds the atomic number Note that the minimum input for each atom consists of giving a name by ATOM and specifying the atomic number by Z All other input given in this category can be derived from these two tokens 4 6 4 Token R cast double The atomic sphere radii can be specified in two different ways In case you want to give absolute values use this token The default is R 0 0 4 6 5 Token R RA cast double As an alternative to the previous token relative atomic sphere radii may be chosen In this case the radii will be scaled to the ASA condition unless you specify a value for FILLNG see below different from one The default value is R RA 1 0 4 6 6 Token LMXL cast integer This token specifies for each atom the maximum angular momentum for the lower partial waves which are taken into account in the secular matrix The default values are derived from the previous input of the atomic number Z 96 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 6 7 Token LMXI cast in
48. 11127D 01 0 5555928693D 01 0 3865169875D 00 0 2324652672D 00 4 0 2285774676D 01 0 2841145833D 01 0 3734102793D 00 0 2291031680D 00 LDER CU NL DMOM1 DMOM2 PMOM1 PMOM2 4 0 0 4157618407D 00 0 1397855137D 01 0 9818797857D 01 0 1037459945D 02 4 1 0 5204308714D 00 0 1637136965D 01 0 5803326913D 01 0 6266815400D 01 3 2 0 3854797793D 00 0 1186359961D 02 0 3679266193D 00 0 1486703663D 01 4 0 2608383567D 01 0 2479774246D 01 0 1204699823D 01 0 1187480604D 01 ESJH CU NL EHAN EBES SHAN SBES 4 0 0 2951559709D 00 0 8072035319D 00 0 6513030651 00 0 5940976548D 01 41 0 5933872823 00 0 8269223615D 00 0 1711121267D 00 0 3107907593D 01 3 2 0 2868397473D 00 0 1101618208D 01 0 3658993068D 01 0 8575664242D 00 4 0 3436334774D 01 0 8512466627D 00 0 1015912559D 01 0 7195771683D 01 A rather complex file check routine is invoked at the beginning of most of the main programs During this check data from each atomic file is read in and com pared to the information gained from previous reading of the CTRL file Whenever inconsistencies arise the program will issue a message and respond adequately For instance if the lattice constant is changed the CTRL file the porgram will identify the inconsistency of the sphere radii In the following the radii will be automatically adjusted and the program enforces an intraatomic restart calculation in order to up date the intraatomic integrals for the secular matrix In contrast if the progra
49. 15 BZSMP 6 0 0 BZINT SMS EMIN 1 0 EMAX 1 5 NDOS 1000 NORD 3 WIDTH 0 01 EFTOL 1 0D 04 SAVDOS F SAVCOOP F CONTROL START QUIT FREE F NITBND 99 CNVG 1 0D 08 CNVGET 1 0D 08 NITATM 50 CNVGQA 1 0D 10 MIXING NMIXB 5 BETAB 0 5 INCBB T NMIXA 5 0 5 SYMLIN NPAN 6 NPTS 400 ORBWGT F CARTE F 2 2 A MORE COMPLICATED STRUCTURE FES2 3T LABEL R ENDPT LABEL g ENDPT LABEL X ENDPT LABEL M ENDPT LABEL R ENDPT LABEL X ENDPT LABEL M ENDPT PLOT CARTV T ORIGIN RPLOT1 RPLOT2 RPLOT3 NPDIV1 5 O10 01010 O CO O 0 O0 o 0 0 1 0 I 5 0 0 0 0 0 0 1 N 0 PDIV2 5 For four types of empty spheres have been added with radii ranging from 0 78 to 1 38 Bohr radii In total 96 empty spheres have been inserted into the pyrite structure Moreover the program has specified optimal radii for iron and sulfur atoms actions taken by the packing program mnpac run are recorded in the output file outpac which among other things contains the results of a final overlap check There the overlap limits are repeated as a default a linear overlap of 1596 is used and all lines with a linear overlap larger than 1096 complemented by one or more exclamation marks Note that an extra overlap bonus is given to the empty spheres due to the flatness of the potential within these spheres 2 2 2 Execution o
50. 282017 ATOM E3 POS 0 461787 0 155170 0 282017 ATOM E3 POS 0 155170 0 217983 0 038213 ATOM E3 POS 0 155170 0 217983 0 038213 ATOM E3 POS 0 344830 0 217983 0 461787 ATOM E3 POS 0 344830 0 217983 0 461787 ATOM E3 POS 0 461787 0 344830 0 217983 ATOM E3 POS 0 461787 0 344830 0 217983 4 POS 0 125076 0 366317 0 027164 4 POS 0 125076 0 366317 0 027164 4 POS 0 374924 0 133683 0 027164 4 POS 0 374924 0 133683 0 027164 4 POS 0 125076 0 133683 0 472836 4 POS 0 125076 0 133683 0 472836 4 POS 0 027164 0 374924 0 133683 4 POS 0 027164 0 374924 0 133683 4 POS 0 133683 0 472836 0 125076 4 POS 0 133683 0 472836 0 125076 4 POS 0 133683 0 027164 0 374924 4 POS 0 133683 0 027164 0 374924 ATOM E4 POS 0 472836 0 374924 0 366317 4 POS 0 472836 0 374924 0 366317 4 POS 0 374924 0 366317 0 472836 4 POS 0 374924 0 366317 0 472836 4 POS 0 366317 0 472836 0 374924 4 POS 0 366317 0 472836 0 374924 4 POS 0 472836 0 125076 0 133683 4 POS 0 472836 0 125076 0 133683 4 POS 0 027164 0 125076 0 366317 4 POS 0 027164 0 125076 0 366317 4 POS 0 366317 0 027164 0 125076 4 POS 0 366317 0 027164 0 125076 SYMGRP GENPOS F SYMOPS R2X T 0 5 0 5 0 0 R3D I ENVEL 0 0
51. AMMA cast double For monoclinic lattices the angle can be specified by the token default value is GAMMA 0 0 4 6 Category CLASS mandatory Once the Bravais lattice has been specified the information about the crystal struc ture is completed by giving the positions of the atoms within the unit cell as well as the species of atoms which hold these sites While the present category com prises all information about the atomic species the atomic sites will be given in the following section of the CTRL file 4 6 CATEGORY CLASS MANDATORY 95 4 6 1 Token NCLASS cast integer number of different atoms which we call classes of atoms can be specified in two different ways The most comfortable and standard procdure consists of letting the programs count the number of ATOM entries just below However in the course of calculations it might be useful to exclude some of the classes listed below from consideration by the program This can be most easily accomplished by shifting the corresponding ATOM entries to the end of this category and reducing the number of classes which are taken into account by the programs by setting NCLASS to the reduced number of classes To summarize if a number of classes is specified by a NCLASS n entry the program tries to reads as many classes Any subsequent ATOM entries are ignored On the other hand if the are less ATOM entries than specified by NCLASS n the program will
52. AT SC CLASS 2 26 ATOM S 27 16 SITE CARTP T ATOM FE POS 0 000000 0 000000 0 000000 5 POS 0 384840 0 384840 0 384840 SYMGRP 05 SYMOPS R2X T 0 5 0 5 0 0 R3D I ENVEL 0 015 BZSMP 6 0 0 BZINT SMS EMIN 1 0 EMAX 1 5 NDOS 1000 NORD 3 WIDTH 0 01 EFTOL 1 0D 04 SAVDOS F SAVCOOP F CONTROL START QUIT FREE F NITBND 99 CNVG 1 0D 08 CNVGET 1 0D 08 NITATM 50 CNVGQA 1 0D 10 MIXING NMIXB 5 BETAB 0 5 INCBB T NMIXA 5 BETAA 0 5 SYMLIN NPAN 6 NPTS 400 ORBWGT F CARTE F LABEL R ENDPT 0 5 0 5 0 5 LABEL g ENDPT LABEL X ENDPT LABEL M ENDPT LABEL R ENDPT LABEL X ENDPT LABEL M ENDPT PLOT CARTV T ORIGIN 0 RPLOT1 1 RPLOT2 0 RPLOT3 0 0 0 NPDIV1 50 NPDIV2 50 oma e O O 0 0 0 1 This representation has an additional advantage In the work on FeS we had to check the influence of atomic displacements on the electronic properties 23 In order to do so the sulfur x value was changed from x 0 38484 to x 0 38084 and 0 38884 With only one 5 atom given in the CTRL file and using the symmetry of the space group this is an easy task As is obvious from Fig 2 9 the crystal structure comprises rather large voids between the atoms However since the standard ASW method is based on the atomic sphere approximation ASA where all space is completely filled by nec es
53. ATM 50 CNVGQA 1 0D 10 MIXING NMIXB 5 BETAB 0 5 INCBB T NMIXA 5 BETAA 0 5 SYMLIN NPAN 5 NPTS 400 ORBWGT F CARTE F 2 1 A SIMPLE CASE CU 13 LABEL W ENDPT 0 500 0 250 0 750 LABEL L ENDPT 0 500 0 500 0 500 LABEL g ENDPT 0 000 0 000 0 000 LABEL X ENDPT 0 500 0 000 0 500 LABEL W ENDPT 0 500 0 250 0 750 LABEL K ENDPT 0 375 0 375 0 750 PLOT CARTV T ORIGIN 0 0 0 0 0 0 RPLOTi 1 0 0 0 0 0 RPLOT2 0 0 1 0 0 0 RPLOT3 0 0 0 0 1 0 NPDIV1 50 NPDIV2 50 It contains a lot more categories and tokens all of which are discussed in de tail in Chap 4 Here we mention in particular the switch to scalar relativistic calculations REL T the types of orbitals used in the calculations as specified by the maximum angular momentum LMXL 2 the principal quantum numbers of all orbitals CONF 4 4 3 4 and the respective orbital occupations QVAL In case you are in doubt about the input for these three tokens just leave them out The program will add them for you Moreover we have specified the number of k points to be used in the Brillouin zone integration by the token NKABC 6 0 0 see Chap 4 Finally categories SYMLIN and PLOT respectively hold information about the lines within the first Brillouin zone along which the band structure is plotted and the region in real space used for plotting the crystal structure as well as the charge density and potential 2 1 2 Execution of the main programs Having generated the CTRL file the ASW progr
54. Cr02af CTRL Cr02fe CTRL_CrOC1 CTRL Crfcc CTRL Crhcp CTRL Cs CTRL CsBr CTRL_CsC1 CTRL_CsI CTRL CsMn Cr CN 6 CTRL CsNi Cr CN 6 CTRL Cu CTRL Cu12 CTRL Cu16 CTRL Cu20 CTRL Cu32 CTRL Cu4 CTRL Cu48 CTRL Cu8 CTRL_CuAlS2 CTRL_CuGaS2 CTRL_CuGaSe2 CTRL_CuGaSe2hetZnSe CTRL_CuInS2 CTRL CuInS2id CTRL CuInS8e2 CTRL_CuS2 CTRL Cu NH3 4804H20 CTRL Dy CTRL_DyNi5 CTRL_Er CTRL_ES CTRL EuB6 CTRL_EuO CTRL_EuS CTRL_Fe CTRL_Fe16 CTRL_Fe2 CTRL_Fe32 CTRL Fe304fcc CTRL Fe304so CTRL Fe304soid CTRL_Fe4 CTRL_Fe48 CTRL_Fe4N CTRL_Fe4Nfe CTRL Fe8 CTRL FeB2 CTRL FeNCrN CTRL MgO CTRL_MgOn CTRL_MgV204 CTRL_MgV205 CTRL_Mn CTRL_Mn2 H20 5Mo CN 7 CTRL Mn38n CTRL_Mn3Snaf CTRL_Mn3Snfe CTRL_Mn4N CTRL_MnAs CTRL_MnBi CTRL_MnO CTRL Mn02 CTRL Mn02af CTRL MnOfcc CTRL MnOtrg CTRL MnOtrgaf CTRL MnW04 CTRL MnW04af 1 CTRL_MnWO4fe CTRL_Mo CTRL_Mo3Si CTRL MoNfcc CTRL_MoNhex CTRL Mo02mon CTRL Mo02mondo CTRL Mo02moni CTRL Mo02monns CTRL Mo02monod CTRL Mo02monoz CTRL_MoO2rut Mo03 CTRL MoSi2 CTRL NOC6 Na CTRL_Na8Si46 CTRL NaC1 CTRL NaCu3Ru4012 NaV205 CTRL NaV205new CTRL_NaV6015 CTRL_NaW2 CTRL_Nb CTRL NbCfcc CTRL NbCr2 CTRL_NbCrAl CTRL_NbFeAl CTRL_NbNiAl 117 CTRL_UMn2Ge2 CTRL_UNi2Ge2 CTRL_UO2 CTRL_UPt3 CTRL_URhAl CTRL_V CTRL_V203LTcm CTRL_V203LTmon CTRL_V203LTmonaf CTRL_V203RTcm CTRL_V203RThex CTRL_V203RTmon C
55. EXAMPLES eV whereas the e states dominate the bands between 1 7 and 5 2 eV The small but finite to configuration mixing is a measure of octahedral distortions i e the deviation from local cubic symmetry Contributions of the Cr 3d states to the oxygen bands are slightly larger for the states which forming bonds experience a larger overlap with the O 2p states For the same reason the bonding antibonding splitting is larger for the states as compared to the ta states which give rise to 7 bonds Chemical bonding is addressed via the COOP or the covalence energy E curves growing out of the plot routine plcop run are displayed in Fig 2 19 Obviously Cr3d Cr3d O2p O2p Cr 3d O2p ECOV E Eg eV Figure 2 19 Partial covalence energies of CrO bonding within the O 2p states hardly contributes In contrast metal ligand overlap is bonding and antibonding in the oxygen and chromium dominated electronic bands this causing most of the stability of the compound Finally metal metal bonding appears in the to and group of bands being antibonding and bonding in the respective lower and upper part As has turned out in previous work on the neighbouring transition metal dioxides inspection of the weighted band structures is a necessary prerequisite for a deeper understanding of these materials This holds especially for the chromium 3d ta levels which we address separately For the
56. Eyert Copyright C 1992 2003 Volker Eyert Please see file COPYRIGHT for details dk dk dt dt dk HH dk dk LoadLeveler specifications 0 class veryshort Specify system and hardware requirements Specify job queue 0 requirements OpSys AIX42 AIX43 amp amp Feature pwr3 3 1 MAIN PROGRAMS AND SHELLSCRIPTS 65 Specify requirements for parallel execution job_type parallel requirements Adapter hps_user min_processors 1 max_processors 14 0 resources ConsumableCpus 1 ConsumableMemory 80 Specify executable done explicitly here see below executable Specify stdin stdout and stderr 0 input dev null 0 output job Cluster Process out 0 error job Cluster Process err Mark job not restartable Q restart no Suppress any notification 0 notification never Finally queue the job 0 queue dk dt dt Gb dt dk dt dk Gb dk dk Gk db dt dk Gb OF Network Queuing System NQS specifications Specify job queue QSUB q high prio Specify CPU time and memory QSUB 1 600
57. KAP of cast integer Number of envelope function energies token EKAP of cast double Array of envelope function energies token EWPAR of cast double Ewald parameter without volume scaling token EWTOL of cast double Precision sought for Ewald sums category BZSMP token NKABC of cast integer and length 3 Number s of k mesh points token BZINT of cast character String for Brillouin zone integration scheme token EMIN of cast double Minimum energy for DOS calculation token EMAX of cast double Maximum energy for DOS calculation token NDOS of cast integer 3 4 DATA FILES 79 214 token token self token token token token token token Number of division of the interval EMIN EMAX BZINT HPS the following two tokens are needed NORD of cast integer Order of approximant in high precision BZ sampling WIDTH of cast double Broadening in high precision BZ sampling BZINT LTM the following token is needed EFTOL of cast double Precision sought for Fermi energy SAVDOS of cast logical Switch to save calculated partial 0055 SAVCOOP of cast logical Switch to save calculated COOPs CTYPE of cast character String for type of calculation MSPLIT of cast logical Switch to calculate m splitted 5 TEMPFD of cast double Temperature for Fermi Dirac folding category CONTROL token token token token token token token token START of cast character String controlling program st
58. Mar 2002 17 02 39 In particular non magnetic CrO turns out to be a metal with a rather high density of states at Within the framework of the Stoner theory of magnetism this is interpreted as a precursor of the ferromagnetic order of this material We display in Fig 2 16 the electronic states along selected high symmetry lines within the E Eg eV Figure 2 16 Electronic bands of CrO along selected symmetry lines within the first Brillouin zone of the simple tetragonal lattice Fig A 5 a first Brillouin zone of the simple tetragonal lattice Fig A 5 a The corresponding density of states DOS is given in Fig 2 17 In Figs 2 16 and 2 17 four groups of bands are identified In the energy range from 7 6 to 1 8 eV we observe 12 bands which trace back mainly to O 2p states but have a non negligible contribution due to the Cr 3d states Bands are most easily counted along the direction X R where they are twofold degenerate The next two groups which extend from 0 8 to 1 7 eV and from 1 7 to 5 2 eV contain six and four bands respectively and originate mainly from Cr 3d states Yet p d hybridization causes additional O 2p contributions in this energy range Finally we observe Cr 4s states starting at 8 0 eV Crystal field splitting expected from the fact that the metal atoms are located at the centers of slightly distorted CrOg octahedra leads to almost perfect energetical separation of the ta and e manifolds of t
59. NKAP 1 EKAP 0 015 EWPAR 2 44949 EWTOL 1 0D 10 NKABC 8 0 0 BZINT SMS EMIN 2 0 EMAX 1 0 NDOS 1000 NORD 3 WIDTH 0 01 EFTOL 1 0D 05 SAVDOS F SAVCOOP F MSPLIT F TEMPFD 300 0 START QUIT FREE F NITBND 20 CNVG 1 0D 08 CNVGET 1 0D 08 NITATM 50 CNVGQA 1 0D 10 NMIXB 5 BETAB 0 5 INCBB F NMIXA 5 BETAA 0 5 ALAT 0 0 PLAT 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SLAT 1 0 BLAT 0 0 CBYA 1 0 CLAT 0 0 GAMMA 90 0 EQUIV T CARTS T PSHIFT 0 0 0 0 0 0 CARTQ T QSWAVE 0 0 0 0 0 0 NPAN O NPTS 400 ORBWGT F SPATH F EPHOT 0 0 CARTE T 82 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE LABEL ENDPT 0 0 0 0 0 0 PLOT CARTV T ORIGIN 0 0 0 0 0 0 RPLOT1 0 0 0 0 0 0 RPLOT2 0 0 0 0 0 0 RPLOT3 0 0 0 0 O NPDIV1 0 NPDIV2 0 NPDIV3 0 task 3 1 0 cpu time 0 00000 sec Execution stopping for HELP T ASW 1 9 program MNSCF ended on majestix at Wed 13 Mar 2002 08 38 28 3 4 9 The atomic files Like most other files the atomic files are created automatically by the main program mnscf run according to the entries ATOM in categories CLASS and SITE of the CTRL file Each atomic file contains all information about the atom at hand Similar to the CTRL file it falls in seven categories named GEN MOMS LDER ESJH VMTA RHOV and CORE They comprise the following data GEN Atomic number angular momenta valence state configuration indica tors for spin polarized and relativistic calculations information about the intraatomic radial mesh core s
60. S t Please wait a moment I m reading the partial DOS Start setting up curve 1 Plot partial f or total DOS t default F For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default E R8 1 1 0 R4 1 1 0 Enter orbital s to be included Note notation of the orbitals refers to the rotated reference frame Select from the classes blank or to complete the list CR 0 1 2 CR Class CR atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 3 all f 1 s 2 y 3 2 4 x 6 2 7 3z 2 r 2 8 Xz 9 x 2 y 2 10 3x 2y y 3 11 xyz 12 5yz 2 yr 2 13 5273 32 72 14 5xz 2 xr 2 15 x 2z y 2z 16 x 3 3xy 2 6 8 9 Class CR atom 2 at 0 500000 0 500000 0 329790 Select from the following orbitals 0 all 1 all p 2 alld 3 all f Tes 2 y 3 2 4 X 6 2 7 3z 2 r 2 8 2 9 x 2 y 2 10 3x 2y y 3 11 2 12 5yz 2 yr 2 13 5273 32 72 14 272 72 15 x 2z y 2z 16 x 3 3xy 2 Select from the classes blank or to complete the list CR 0 1 2 The following orbitals have been selected Class CR atom 1 orbital yz Class CR atom 1 orbital xz Class CR atom 1 orbital x 2 y 2 Enter scaling factor default 1 0 Broadening of this curve t or not f default Select curve style default 1 A marks styles already selected solid green 1 dashedi blue 2 48 CHAPTER
61. Sec 2 1 3 If output should be prepared for Gnuplot the program usually creates a file bnd ps which holds a postscript copy of the plot particular nice feature arises from specifying writing to a IXTEXfile This will produce a file bnd tex Next you have to invoke the shellscript plbnd Ix see below which will run EXTEXon a file named plbnd tex into which bnd tex is included via BTRX s input command As result in case the band structure is not too complicated hence file bnd tex is not too large a final file bnd ps is created This LXTEXoption is particularly suited for plotting weighted band structures In the latter situation another important feature comes in First you are asked to specify the orbitals to be included Actually the program plots for each k point and band the projection of a particular orbital onto the full wave function Furthermore the program allows to specify the coordinate system within which the orbitals are selected This is particularly useful when the crystal field split d orbitals of a transition metal atom are to be considered as in the prvious examples of FeS5 or for this reason the plot routine asks for a rotation matrix which can be given in the same form as the symmetry matrices in token SYMOPS of the 3 3 INSTALLATION SHELLSCRIPTS 73 CTRL file See Chap 4 for more details and examples Alternatively the string characterizing the rotation can be written to a file named ROTS In that
62. THE ASW PROGRAMS EXAMPLES 3 DOS 8 6 4 2 0 2 4 6 8 E Eg eV Figure 2 24 Partial densities of states DOS of ferromagnetic CrO per for mula unit DOS can be further decomposed in the single d components The results for the 3d 15 states are shown in Fig 2 25 Worth mentioning is the up and downshift of all DOS 1 eV E Eg eV Figure 2 25 Partial Cr 3d tz DOS of ferromagnetic CrO Selection of orbitals is relative to the local rotated reference frame three spin up and spin down partial DOS as compared to the spin degenerate case Fig 2 18 which is responsible for the decrease of the DOS at In agreement with the Stoner criterion it causes an energy gain especially for the spin up d 2_ 2 like 2 3 A MAGNETIC SYSTEM CRO 59 electrons In contrast less energy has to be paid by the spin down electrons since the sharp peak of the d 2_ 2 partial DOS was above already in the non magnetic case 2 3 4 Spin polarized antiferromagnetic calculations As already mentioned above CrO shows an instability towards antiferromagnetic order if the lattice constants a and c or the the oxygen parameter u are changed 26 In the present section we demonstrate how the calculations for an antiferromagnet could be efficiently performed Again the CTRL file and the atomic files of the converged spin polarized calculation for ferromagnetic CrOs should be first copied to a different directory After t
63. TOM S POS 0 384840 0 115160 0 115160 SYMGRP GENPOS F SYMOPS R2X T 0 5 0 5 0 0 R3D I ENVEL 0 015 BZSMP 6 0 0 BZINT SMS EMIN 1 0 EMAX 1 5 NDOS 1000 NORD 3 WIDTH 0 01 EFTOL 1 0D 04 SAVDOS F SAVCOOP F CONTROL START QUIT FREE F NITBND 99 CNVG 1 0D 08 CNVGET 1 0D 08 NITATM 50 CNVGQA 1 0D 10 MIXING NMIXB 5 BETAB 0 5 INCBB T NMIXA 5 BETAA 0 5 SYMLIN NPAN 6 NPTS 400 ORBWGT F CARTE F LABEL R ENDPT 0 5 0 5 0 5 LABEL g ENDPT 0 0 0 LABEL X ENDPT 0 5 0 0 0 0 0 0 0 2 2 A MORE COMPLICATED STRUCTURE FES 29 LABEL M ENDPT LABEL R ENDPT LABEL X ENDPT LABEL M ENDPT PLOT CARTV T ORIGIN RPLOT1 RPLOT2 RPLOT3 NPDIV1 5 OOo aaa O1 gt OO 0 0 PDIV2 5 OO gt 0 0 0 1 0 Due to the symmetry of the crystal the simple cubic cell comprises four iron eight sulfur atoms in total The crystal structure is shown in Fig 2 9 In this plot Figure 2 9 Crystal structure of 52 Iron and sulfur atoms are printed in red and green respectively the origin has been shifted by half the cell edge see token ORIGIN 0 5 0 0 0 0 in category PLOT As a consequence one Fe atom is observed in the center of the plot while atoms of the sulfur pair appear in the upper right and lower left corner The pyrite crystal structure is best described in terms of the NaCl structure with the sublattices occupied by iron
64. TRL_CoO CTRL_CoOfcc CTRL CoOtrg CTRL_CoOtrgaf CTRL_CoS2 CTRL_CoSb3 CTRL_Cofcc CTRL_Cohcp CTRL_Cr CTRL_CrO2 CHAPTER 5 THE ASW DATABASE CTRL_La CTRL La2BaCu05 CTRL_La2BaCu0bafc CTRL_La2BaCu05afn CTRL La2BaCu05afp CTRL_La2BaCu05fe CTRL La2BaCu05fenew CTRL_La2BaCu05new CTRL_La203 CTRL_La5Ti5017 CTRL_LaA12 CTRL_LaB6 CTRL_LaCu3Ru4012 CTRL_LaF3 CTRL_LaI2 CTRL_LaMgBO CTRL LaMn03sc CTRL LaMn03so LaMn03soaf CTRL_LaNi5 CTRL_LaNi5H7 CTRL_LaTi03 CTRL_LaTi03sc CTRL_Li CTRL Lii128i7 CTRL_Li2FeS2 CTRL_Li2RuS2 CTRL Li2W04 CTRL_Li3FeN2 CTRL_LiF CTRL LiH CTRL LiMn204 CTRL LiTi204 CTRL LiTi204id CTRL LiV204fcc CTRL LiV204fccid CTRL LiV204tri CTRL LiV204triid CTRL_LiYF4 CTRL_Lu CTRL_Lu203 CTRL_LuA13 CTRL_LuCu4Au CTRL LuCu4Pd CTRL Mg CTRL Mg2Ge CTRL_Mg2Si CTRL_MgB2 CTRL_MgGa204 CTRL_TaS2 2H CTRL_TaS2E 1T CTRL_TaS2E 2H CTRL_TaS2Na 1T CTRL_TaS2Na 2H CTRL_TaSe2 1T CTRL_TaSe2 2H CTRL_TaTe2 CTRL_Tb CTRL_Tc CTRL_Th CTRL_Ti CTRL_Ti203dM CTRL_Ti203dY CTRL_Ti203h108 CTRL_Ti203h14 CTRL_Ti203h202 CTRL Ti203h296 Ti203ht CTRL Ti203rt CTRL_Ti509LT CTRL_Ti509RT CTRL_TiB CTRL_TiCfcc CTRL_TiCr2 CTRL_TiFeAl CTRL Ti02 CTRL Ti32 CTRL_TiTe2 CTRL_T1 CTRL_T1Br CTRL_T1C1 CTRL T1I CTRL Tm CTRL_TmA13 CTRL_U CTRL U3Co4Ge7 CTRL_UA13 CTRL_UB2 CTRL_UB4 CTRL_UB6 CTRL_UCo2Ge2 CTRL_UCo2Ge2feh CTRL_UCo2Ge2fel CTRL_UCoSn CTRL_UCr2Ge2 CTRL_UCu2Ge2 CTRL_UFe2Ge2 CTRL_UGe3 CTRL
65. TRL_V203RTmonaf CTRL_V203RTtri CTRL_V205 CTRL_V205id CTRL_V205idd CTRL_V205idz CTRL_V205sco CTRL_V305HT CTRL_V305LT CTRL_V407LT CTRL_V407RT CTRL_V407RTjp CTRL_V407id CTRL V5O9LT CTRL V5O9RT CTRL V6011LT CTRL V6011RT CTRL VH CTRL VO CTRL_VO2mon1 CTRL_VO2mon1i CTRL V02moniw CTRL_VO2mon1x10 CTRL_VO2mon1x20 CTRL_VO2mon1x60 CTRL_VO2mon2 CTRL_VO2mon2af CTRL_VO2mon2afx20 CTRL_VO2mon2afx40 CTRL_VO2mon2afx60 CTRL_VO2mon2x20 CTRL_VO2mon2x40 CTRL_VO2mon2x60 CTRL_VO2rut CTRL_VO2rutw CTRL V Cr CN 6 CTRL W 118 CTRL 0 1 CTRL FeO0fcc CTRL FeOtrg CTRL_FeOtrgaf CTRL_FeS2 CTRL_FeSi CTRL_FeSi2 CTRL_FeTi CTRL FeW04 CTRL FeWO4af1 CTRL FeWO04fe CTRL Ga CTRL Ga203 CTRL Ga203tri CTRL GaAs CTRL_GaP CTRL_GaSb CTRL_Gafcc CTRL Gd CTRL Gd2028 CTRL GdAg CTRL_GdAgaf001 CTRL_GdAgaf110 CTRL GdAgaf111 CTRL GdA12 CTRL 645 CTRL GdSscaf CTRL GdStrg CTRL GdStrgaf CTRL_GdTi03 CTRL_GdZn CTRL_GdZnaf001 CTRL_GdZnaf110 CTRL GdZnaf 111 CTRL Ge CTRL Ge02 CTRL_H CTRL_He CTRL Hf CTRL Hf A13 CTRL HfSe2 CTRL Hg CTRL HgMg3 CTRL Ho CTRL In CTRL In203 CTRL In203b1 CTRL In203id CTRL In203s1 CHAPTER 5 THE ASW DATABASE NbO2bct NbO2bctb CTRL NbO2bctbi NbO2rut NbSe2 2H CTRL Nd CTRL_Nd2BaCu05 CTRL_NdCu3Ru4012 CTRL_Ne CTRL_Ni CTRL 1 CTRL Ni3C CTRL NiF2 CTRL NiO NiO0fcc CTRL NiOtrg CTRL NiO0trgaf CTRL N
66. The Augmented Spherical Wave Method An Extended User Guide Version 1 9 Volker Eyert April 14 2005 Copyright C 1999 2003 Volker Eyert rights reserved Contents 1 Introduction zONSSEVISN 85 6 dnd Ete dou le oo Moules rog lesen 6 1 2 Physical background Ton Programming aee E cs 14 stallation siket a h eed pg eg 1 5 Linking with other software eG matters s aa 2a air Tr Known DUPS C ess me giei E e 1 8 Acknowledgement 2 Execution of the ASW programs Examples 2 1 A simple caset Cuis Th Kuchen 243 OFRE a te are aus 2 1 2 Execution of the main programs 1134 144409 e 2 1 3 Execution ofthe plot programs 2 1 4 Advanced features 2 1 5 Crystal orbital overlap 2 1 6 Fermi surface e sota tels e uu e xum 2 2 more complicated structure 5 2 2 1 CTRL file and sphere packing 2 2224 2 2 2 Execution ofthe main programs 2 2 3 Execution ofthe plot programs 2 3 magnetic system CrOg 2 3 1 CTRL file and
67. a consequence the d 2_ 2 peak appears near the Fermi energy and contributes to the rather large DOS at Furthermore it is responsible for the increase in total energy as compared to ferromagnetic CrO 2 8 MAGNETIC SYSTEM CRO 61 E Ep eV Figure 2 26 Electronic bands of antiferromagnetic along selected sym metry lines within the first Brillouin zone of the simple tetragonal lattice Fig A 5 a DOS 1 eV E Eg eV Figure 2 27 Partial DOS of antiferromagnetic CrO per formula unit 62 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES DOS l eV E Eg eV Figure 2 28 Partial Cr 3d DOS of antiferromagnetic CrO2 Selection of orbitals is relative to the local rotated reference frame Chapter 3 Organization of the ASW program package In the present chapter an overview over all files coming with the distribution is given This includes mainly four groups While the calculations are performed by one of the main programs the plot programs serve the purpose of visualizing the results Work of both steps is made easier by a bunch of shellscripts Finally a list of all files which are either included in the distribution or else created by one of the programs is given 3 1 Main programs and shellscripts In the present section all main programs of the ASW distribution are discussed In contrast to the plot programs presented in the following section all main programs w
68. addition if you type amp arbitrary text the title will be constructed from the first line of the CTRL file complemented by the arbitrary text 3 2 1 plstr run plstr x This program starts from file STRU which holds atomic positions and radii of all atoms within the plot region specified by tokens ORIGIN and RPLOTn and prepares for later use of RasMol or XMakemol During the dialog colours and sizes of the atomic spheres as well as the plot perspective can be specified 3 2 2 plfre run plfre x This program starts from file FREE which holds the overlapping free atom charge densities and potential within the plot region specified by tokens ORIGIN and RPLOTn It prepares for later use of Gnuplot During the dialog you can choose between a contour or 3D plot In addition plot of the core charge density valence charge density or both or else the potential can be specified 3 2 3 plbnd run plbnd x This program allows for plotting of the weighted band structure It start from file BNDE containing the E k for all bands and if token ORBWGT T has been specified from file BNDV which holds the corresponding eigenvectors These data are prepared for later plotting with either Gnuplot or IATEX In the latter case the shellscript plbnd lx cwhas to be used in addition During the dialog invoked by calling plbnd x among other things the energy scale and reference as well as the energy window must be specified example has been given in
69. am for self consistent field calcula tions can be started by typing mnscf run at the operating systems prompt However for Unix Linux systems the distribution offers several useful shellscripts Here we just type mnscf x at the systems prompt which starts a background job with the output sent to file outscf The program will use about 13 iterations to full conver gence On a standard PC the total execution time will be about 2 3 seconds After completion the output file outscf contains all the information collected during the iterations In addition a file named CU the naming is due to the token ATOM in categories CLASS and SITE has been created which contains all information specific to the respective atom These data are needed by the program For this reason you should not delete an atomic file or change it by hand Otherwise the program might have to start from scratch again There has been a quite complicated file checker implemented which detects the status of all atomic files and after that decides which calculation can be performed Once self consistency has been achieved you are able to calculate the band struc ture by typing mnbnd run or better mnbnd x This program uses the information contained in the files CTRL and CU and generates a new file called BNDE which comprises the eigenvalues for each k point hence the band structure Output is stored in file outbnd Calculation of the band structure will take about half a second
70. amount lower than the maximum a consequence the deviation from the mximum potential along a path can be used to define the overlap region of two spheres This is done by token POTWIN default value is POTWIN 0 0 Note that this token is kept mainly for consistency reasons 4 10 CATEGORY ENVEL 101 4 9 9 Token RADACC cast double Here you can specify the accuracy required for the sphere radii The default value of RADACC 0 02 hardly needs a change 4 9 10 Token POSACC cast double This token gives the accuracy required for the empty sphere positions As before the default value of POSACC 0 003 usually is sufficient 4 10 Category ENVEL The ASW method got its name from the way basis functions for a subsequent variational procedure are constructed To be specific we start out from analytically known solutions of Schr dinger s equation with a constant potential which are either plane waves or spherical waves In the ASW method only the latter used in the form of spherical Hankel functions Within the atomic spheres these spherical waves are replaced or augmented by the solutions of Schr dinger s equation with the actual potential The present category specifies the analytical solutions outside the atomic spheres which are the socalled envelope functions The region outside the spheres is called the interstitial region The tokens this category usually need not be changed from their default value Hen
71. arting point QUIT of cast character String controlling program end point FREE of cast logical Switch to free atom calculations free electron bands NITBND of cast integer Maximum number of band iterations CNVG of cast double Convergence tolerance for zero moments CNVGET of cast double Convergence tolerance for total energy NITATM of cast integer Maximum number of intraatomic iterations CNVGQA of cast double Convergence tolerance for atomic charges category MIXING token token token token token NMIXB of cast integer Number of previous iterations used in band mixing BETAB of cast double Mixing parameter for band mixing INCBB of cast logical Switch to increase band mixing parameter NMIXA of cast integer Number of previous iterations used in atom mixing BETAA of cast double Mixing parameter for atom mixing category SUPCELL token token ALAT of cast double Supercell lattice constant A in UNITS PLAT of cast double and length 9 OR Supercell primitive translations in units of A 80 token token token token token token token token token token token categor token token token token token token token token token categor token token token token token CHAPTER 3 ORGANIZATION OF THE ASW PROGRAM PACKAGE SLAT of cast character String for supercell Bravais lattice BBYA of cast double OR Ratio of the supercell lattice constants B A BLAT of cas
72. ated to the LMTO method since most early calculations were done with the pure ASA For this reason calculations employing the combined corrections earned an extra bonus In contrast these corrections to the ASA were included in the ASW method in a very elegant manner from the very beginning and hence calculations without the combined corrections actually were never done Hence the default is CCOR T 4 4 10 Token FULPOT cast logical In future versions this token will allow for full potential ASW calculations 4 4 11 Token CORDRD cast logical For some instances as e g calculation of rather small energy differences it might be necessary to freeze the core state during the self consistency cycle This is allowed for by setting CORDRD T Yet the default is CORDRD F Note that in case of frozen core calculations the last of the aforementioned categories contained in the atomic files i e the category CORE must not be deleted from the file after successful convergence As a consequence for CORDRD T specifying CLEAN T will remove only the categories VMTA and RHOV from the atomic files but will preserve the category CORE 4 5 CATEGORY STRUC MANDATORY 93 4 5 Category STRUC mandatory This category holds all the information about the Bravais lattice Of course its presence is necessary for any calculation 4 5 1 Token UNITS cast character Here you can choose the units to be used for the following tokens which may be at
73. atoms and the centers of gravity of sulfur atom pairs respectively These sulfur dumb bells are oriented along the 111 axes Being 2 161 their bond length is still shorter than the Fe S distance of 2 265 30 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES Whereas the sulfur atoms are tetrahedrally coordinated by one sulfur and three iron atoms the six nearest neighbour sulfur atoms at each iron site form slightly distorted octahedra The distorted FeSg octahedra are interlinked by common corners and due to the formation of the 111 sulfur pairs have rotated away from the cartesian axes by about 23 For a two dimensional crystal the situation is sketched in Fig 2 10 Obviously the formation of the 111 sulfur pairs does not destroy the square Figure 2 10 Two dimensional analogue of the pyrite structure Big and small filled circles designate iron and sulfur atoms respectively Small open circles mark the ideal positions of the rocksalt structure planar coordination of the iron atoms Instead the squares built by the sulfur atoms just shrink and rotate Since the orientation of the dumb bells conforms with the cubic point group the underlying Bravais lattice is no longer face centered but simple cubic and the unit cell comprises four formula units In the CTRL file listed above we have already included information about the crystal symmetry in category SYMGRP It contains two tokens namely SYMOPS for a mi
74. aults 9 9 DOStop 5 222992 1 eV DOSmax 6 000000 1 eV Enter new DOSmax to change this default Enter energetic position of curve labels to 9 x 2 y 2 e the list rence frame is ignored already selected 2 4 6 8 0 3869 eV 0 4067 eV 3 2636 eV relative to EF relative to EF use default 2 3 MAGNETIC SYSTEM 51 task 1 total cpu time 0 02000 sec ASW 1 9 program PLDOS ended on majestix at Thu 14 Mar 2002 15 00 25 Note that after the first input of the rotation matrix R8 1 1 0 R4 1 1 0 it is kept as default for the following curves However the program detects the selection of all p orbitals for the oxygen partial DOS and notifies the user that the rotation can be ignored in this case The single components of the partial DOS making the t and manifolds are displayed in Fig 2 18 where again we have included only the single chromium atom 4 DOS 1 eV DOS 1 eV E Eg eV Figure 2 18 Partial Cr 3d tg and densities of states DOS of CrO Selec tion of orbitals is relative to the local rotated reference frame at 0 0 0 and used the local rotated reference frame As in Fig 2 17 the almost perfect energetical separation of the 3d ts and groups of bands is clearly revealed former states appear almost exclusively in the energy range from 0 8 to 1 7 52 CHAPTER 2 EXECUTION THE ASW PROGRAMS
75. by the entries qdiff and ediff 3 2 Plot programs and shellscripts The plot programs coming with the distribution are distinguished from the main programs in that they do are completely independent of the CTRL file but start from files created by one of the main programs As for the main program there exist both executables with ending run and corresponding shellscripts with ending x which latter call the executables and include an automatic call of the respective plot program as Gnuplot RasMol or XMakemol In addition intermediate files are deleted at the end Whenever these files are needed e g for exchange with other plot porgams one should employ the executable rather than the shellscript Again we will use the names program exe cutable and shellscript synonymously in the following discussion an extra service to the user all specifications of the plot as entered during the dialog are echoed to a file PLIx where x S F B D or depending on the plot porgram After the name of this file has been changed it can be edited and used for new plots by typing e g mnbnd run lt PLIBnew or mnbnd x PLIBnew 72 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE Another feature common to all plot programs concerns the title of the plot On invoking any of the plot programs one is asked for specifying the title Entering a here will make the program use the title given by the first line of the CTRL file In
76. calculation We will come back to this point below Of course the corresponding charges as given by token QVAL are all zero The file CNEW looks like the following HEADER FeS2 sc data by E D Stevens M L DeLucia and P Coppens Inorg Chem 19 813 1980 VERSION ASW 2 0 IO HELP F SHOW T VERBOS 30 CLEAN T OPTIONS REL T OVLCHK T STRUC ALAT 10 23476 SLAT SC CLASS 2 26 R RA 2 33212 LMXL 2 CONF 4 4 3 4 COORB 2 QVAL 2 0 0 0 6 0 0 0 ATOM S 7 16 R RA 2 25163 LMXL 2 CONF 3 3 3 4 COORB 1 QVAL 2 0 4 0 0 0 0 0 1 Z 0 R RA 1 38299 LMXL 0 CONF 1 2 3 QVAL 0 0 0 0 0 0 2 Z 0 R RA 1 04353 LMXL 0 CONF 1 2 3 QVAL 0 0 0 0 0 0 Z 0 R RA 0 77989 LMXL 0 CONF 1 2 QVAL 0 0 0 0 4 Z 0 R RA 0 78798 LMXL 0 CONF 1 2 QVAL 0 0 0 0 SITE CARTP T ATOM FE POS 0 000000 0 000000 0 000000 ATOM FE POS 0 000000 0 500000 0 500000 ATOM FE 05 0 500000 0 000000 0 500000 ATOM FE 05 0 500000 0 500000 0 000000 ATOM S POS 0 384840 0 384840 0 384840 ATOM S POS 0 115160 0 384840 0 115160 ATOM S 05 0 384840 0 384840 0 384840 2 2 MORE COMPLICATED STRUCTURE FES 5 5 ATOM S ATOM S ATOM S ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E1 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2 ATOM E2
77. ce in most cases you can ignore this category at all 4 10 1 Token NKAP cast integer Here the number of envelope functions i e the number of analytical solutions outside the atomic spheres per atom and angular momentum are fixed The default is NKAP 1 4 10 2 Token EKAP cast double is used to specify the energies of the solutions of Schr dinger s equation in the interstitial region The default value for the first solution is EKAP 0 015 which is the classical ASW value 4 10 3 Token EWPAR cast double The Ewald parameter is used to calculate the expansion of spherical Hankel functions centered at a specific atomic site in terms of spherical Bessel functions centered at a different site Following a seminal method first proposed by the Ewald the resulting lattice sums are cut into two the cutoff being the Ewald parameter The default value is EWPAR 2 44949 102 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 10 4 Token EWTOL cast double Using the token EWTOL you can specify the precision sought for the convergence of the aforementioned lattice sums The default is EWTOL 1 0D 10 4 11 Category BZSMP The category BZSMP holds all information related to the Brillouin zone sampling 4 11 1 Token NKABC cast integer length 3 This token specifies the numbers of mesh points to be taken along each of the reciprocal space primitive translations As such it determines the k space grid used for the Brillouin zone in
78. chaindashed3 gray 9 Enter curve label to suppress Cu 3d e_g Please wait a moment I m working on this curve Set up more curves t Default is f Center of gravity of DOS curve 1 Spin 1 EF 0 8963 eV Center of gravity of DOS curve 2 Spin 1 EF 2 3616 eV Center of gravity of DOS curve 3 Spin 1 EF 2 3706 Center of gravity of DOS curve 4 Spin 1 2 6160 Indicate center of gravities f default Ebot 10 065942 eV Etop 11 669161 eV relative to EF Emin 11 000000 eV Emax 6 000000 eV relative to EF Enter new Emin Emax to change these defaults 10 6 2 1 SIMPLE CASE CU 21 DOStop 3 772949 1 eV DOSmax 4 000000 1 eV Enter new DOSmax to change this default Enter energetic position of curve labels to use default task 1 total cpu time 0 01000 sec ASW 1 9 program PLDOS ended on majestix at Fri 08 Mar 2002 18 41 10 This dialog is much more complex than the one before since we generated four curves and deviated from the default settings The resulting plot is shown in Fig 2 2 where we identify the partial DOS corresponding to the Cu 4s 4p and 3d 4 DOS 1 N Ep eV Figure 2 2 Partial densities of states of Cu orbitals The latter have been split into their t and e components as resulting from the cubic crystal field splitting In particular we observe rather small 4s and 4p contributions in the
79. ctions charge densities and using the notions of density func tional theory the intraatomic potentials The latter in turn allow evaluation of the intraatomic integrals for use in the secular matrix This part is called the atomic part At start up of the program guessed moments of the partial DOS are used to boot execution with the atomic calculations Finally since the moments are stored in the atomic files they may be used to restart a calculations again beginning with the intraatomic part To conclude four different starting points of the programs execution can be distinguished which may be selected by token START but of course also depend on the information gained in previous executions START REN Execution starts from scratch The program performs a renormal ized atom calculation using the charges as specified by QVAL and magnetic moments as given by MVAL respectively In contrast if FREE T has been given a free atom calculation is performed using a sphere radius of 20 Bohr radii START RST In this case the program does a restart calculation i e a renor malized atom calculation with the partial charges and logarithmic derivatives as specified in the atomic files START ATM program invokes one or more full band iterations starting with the intraatomic calculations The number of band iterations to be done is specified by token NITBND START BND This is the default The program invokes one or more full band ite
80. d and both the band struc ture and the partial DOS been calculated we turn to the plotting Typing plbnd x and following the dialog we obtain the band structure displayed in Fig 2 12 Five E Ey eV Figure 2 12 Electronic structure of FeSs along selected symmetry lines of the first Brillouin zone of the simple cubic lattice see A 1 groups of bands are observed While two groups are found below 10 eV a wide group shows up between approx 7 5 and 2 eV Just below and above the Fermi energy a rather narrow and a wide group follow These latter two groups are sepa rated by an optical band gap of z 0 7 eV Note that all energies are referred to the valence band maximum predominant orbital character of these five groups is read off from the partial densities of states as shown in Fig 2 13 Obviously the lowest two groups are made 2 2 A MORE COMPLICATED STRUCTURE 39 30 N N DOS 1 yk E Ey eV Figure 2 13 Partial densities of states of FeSo exclusively from the semicore like S 3s states whereas the higher lying states trace back to a mixture of Fe 3d and 3p bands The latter orbitals dominate especially the wider groups between approx 7 5 and 2 eV as well as between 2 7 and 4 5 eV In contrast the sharp peak just below Ey is due almost exclusively to the Fe 3d states We will learn about a means for a more detailed analysis of these states below For the t
81. d to specify e g a different energy interval Just edit file PLIBf and type plbnd x PLIBf again Yet since file PLIB is just simple echo you should not change the order of the lines Next we are going to plot the partial densities of states Now typing pldos x you enter the following dialog ASW 1 9 program PLDOS started on majestix at Fri 08 Mar 2002 18 41 10 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details All input will be echoed to file PLID Enter terminal type 2 1 SIMPLE CASE CU X Windows default PC Screen vt220 emulation suppress terminal output Enter output device 1 2 3 4 5 6 7 8 9 2 Postscript default Color postscript LaTeX LaTeX VE s way HP LaserJet III PCL5 HP LaserJet II GIF leave the decision for later suppress output to file Enter title Energies in Rydberg f or eV t default DOS scaled accordingly Energies relative to MTZ 0 or EFermi F default Portrait P default landscape L or encapsulated postscript plot E E Energy axis to the top f or right t default Plot DOS f default or integrated DOS t Please wait a moment I m reading the partial DOS Start setting up curve 1 Plot partial f or total DOS t default f For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default E Enter orbital s to be includ
82. default is QSWAVE 0 0 0 0 0 0 4 15 Category SYMLIN This category comprises all the information needed for plotting the band structure 4 15 1 Token NPAN cast integer This token holds the number of panels which is the number of different symmetry lines in the Brillouin zone along which the band structure is represented The default is NPAN 0 However note that for this token the same as for tokens NCLASS and NBAS holds The number of symmetry lines will be calculated from the following entries but token NPAN can be used to hide additional entries from the program 4 15 2 Token NPTS cast integer Here you can give the maximum number of points to be used for the band structure plot The actual number will be calculated by the program and usually will be slightly less than the input given by this token The default is NPTS 400 However in case you choose to calculate orbital projected band structures see below you should use NPTS 200 4 15 3 Token ORBWGT cast logical This switch allows to plot orbital projected band structures If ORBWGT T is selected the program will print out the eigenvectors for each k point in addition to the eigenvalues This allows to evaluate the contribution from each orbital of the basis set to the wave function at each k point and for each band which may be represented as the width of a bar attached to each E k in the plot The default is ORBWGT F 4 15 4 Token CARTE cast logical This
83. density approximation LDA coming with DFT By now all common parametrizations have been imple mented Alternatively the generalized gradient approximation in all known parametrizations can be used As all other augmentation schemes the method is built upon a special form of the muffin tin approximation MTA namely the atomic sphere approximation ASA as invented by Andersen It is characterized by the requirement that the atomic spheres must fill space completely Inside the spheres the potential as well as the charge densities are assumed to be spherical symmetric While this socalled shape approximation of both the and the ASA might seem as crude approximations to the full crystal potential the ASA actually is not This can be readily understood from the fact that the ASA condition creates overlap regions in the bonding region between two atoms In these regions the sum of the two ASA potentials experiences an effective downshift as compared to the potentials of the single spheres and thus mimics the full potential quite well Indeed electronic properties calculated using ASA based methods can be hardly distinguished from those growing out of the much more elaborate full potential methods However due to the spherical symmetry and the overlap of the potential wells calculated total energies still lack the accuracy needed e g for calculating elastic constants of phonon frequencies For this reason I have implemented a new full
84. double and length 9 mandatory OR Primitive translations in units of A SLAT of cast character String for Bravais lattice BBYA of cast double OR Ratio of the lattice constants BLAT of cast double Lattice constant B in UNITS CBYA of cast double OR Ratio of the lattice constants CLAT of cast double Lattice constant C in UNITS GAMMA of cast double Angle used for the monoclinic lattices category CLASS mandatory token token token token token token token token token token token NCLASS of cast integer Number of different atoms classes ATOM of cast character mandatory Class labels Z of cast integer mandatory Atomic numbers R of cast double OR Atomic sphere radii in atomic units R RA of cast double Atomic sphere radii in arbitrary units LMXL of cast integer Maximum angular momentum including the lower waves LMXI of cast integer Maximum angular momentum including intermediate waves CONF of cast integer and length 4 Principal quantum numbers for all orbitals COORB of cast integer Orbitals to be included in the COOP QVAL of cast double and length 4 Valence charges for starting from scratch MVAL of cast double and length 4 Valence moments for starting spinpolarized calculations category SITE mandatory token token token token token NBAS of cast integer Number of atoms CARTP of cast logical Switch to trea
85. e files plbnd tex pldos tex and plcop tex respectively and run KIEXas well as dvips As a result postscript files bnd ps dos ps and coop ps respectively are obtained 3 2 7 plbnd tex pldos tex plcop tex These are files used to include bnd tex dos tex and coop tex respec tively and to produce postscript files of the band structure DOS or COOP 3 3 Installation shellscripts 3 3 1 Makefile This is the makefile of the ASW program package for compiling and linking the source and object files in a Unix Linux environment Typing make all will automat ically create all executables and typing make install will install them in a prespecified directory A full description of this process has already been given in Sec 1 4 74 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE 3 3 2 mkall x The compiling and linking step can be performed as a background job by invoking the shellscript mkall x 3 3 3 upshl This shellscript updates the specification of the directory where the executables are installed in all shellscripts listed in Secs 3 1 and 3 2 It is automatically called during the make install process 3 4 Data files Input data as well as data created by the ASW programs are spread over a large number of files Yet exchange of the user with the programs is limited essentially to a single file i e the CTRL file other files serve the purpose of holding specific information about the
86. ects the d 2_y2 orbital However before the rotation matrix has to be given in the same form as for program pldos run above Since was requested the plot routine plbnd run writes to the file bnd tex from which the postscript file bnd ps is created by invoking the shellscript plbnd lx The corresponding results for 2 3 MAGNETIC SYSTEM CRO 55 the dz and dyz orbitals are shown in Figs 2 21 and 2 22 The following features 2 0 1 5 1 0 Le r d Le 0 0 1 0 rx RZ E RA 7 Figure 2 21 Weighted electronic bands of CrO The width of the bars given for each band indicates the contribution due to the orbital of the Cr atom at 0 0 0 relative to the local rotated reference frame R A M 7 Figure 2 22 Weighted electronic bands of The width of the bars given for each band indicates the contribution due to the 3d orbital of the Cr atom at 0 0 0 relative to the local rotated reference frame are worth mentioning On relating Fig 2 20 to the Brillouin zone of the simple tetragonal lattice Fig A 5 a we observe negligible dispersions along all lines within 56 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES the planes spanned by the either the points X and or else the points Z R and A In contrast dispersion along all lines connecting these plains is about 0 8 eV Thus one finds a predominantly one dimensional behavio
87. ed Class CU atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 3 all f 1 s 2 y 3 2 4 x 6 2 7 3z 2 r 2 8 2 9 x 2 y 2 10 3x 2y y 3 11 xyz 12 5yz 2 yr 2 13 5273 32 72 14 5xz 2 xr 2 15 x 2z y 2z 16 x 3 3xy 2 1 The following orbitals have been selected Class CU atom 1 orbital s Enter scaling factor default 1 0 Broadening of this curve t or not f default 17 18 Select curve style default solid green 0 dashed2 red 3 dashdottedi cyan 5 chaindashedi black 7 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES 1 A marks styles already selected dashedi blue 2 dotted magenta 4 dashdotted2 yellow 6 5 chaindashed2 coral 8 3 chaindashed3 gray 9 Enter curve label to Cu 4s suppress Please wait a moment I m working on this curve Set up more curves t Default is f t Start setting up curve 2 Plot partial f or total DOS t default f For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default E Enter orbital s to be included Class CU atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 allp 2 alld 3 all f 158 2 y 3 2 4 x 6 2 7 3z 2 r 2 8 2 9 x 2 y 2 10 3x 2y y 3 11 2 12 272 72 13 52 3 3zr 2 14 b5xz 2 xr 2 15 x 2z y 2z 16 x 3 3xy
88. energy The default value is EMAX 1 0 Ryd 4 11 5 Token NDOS cast integer Token NDOS gives the number of divisions of the EMIN EMAX Choosing a small value will result in inaccuracies of the calculated densities of states However a too high value will produces some statistical noise in the simple sampling scheme A good choice is NDOS nnnn where nnnn is 1000 times the width of the energy interval in eV The default is NDOS 3000 4 11 6 Token NORD cast integer In case that BZINT HPS has been specified the following two tokens are needed Token NORD fixes the order of the approximant in the high precision Brillouin zome scheme of Methfessel and Paxton While low values might cause inaccuracies high values might lead to too sharp structures A good choice is NORD 3 which is the default 4 11 7 Token WIDTH cast double This token specifies the internal broadening used for the high precision Brillouin zome scheme The default value is WIDTH 0 01 Ryd 4 11 8 Token EFTOL cast double In case that BZINT LTM has been specified the following token is needed in future versions Token EFTOL gives the desired accuracy for the calculation of the Fermi en ergy 104 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 11 9 Token SAVDOS cast logical Since the calculation of the partial m resolved densities of states DOS requires additional CPU time token SAVDOS has been implemented to switch of calcula
89. entries for the fractional translations are inter preted as Cartesian coordinates CART T T or as relative components in terms of the primitive translations CARTT F The default value is CARTT T 4 9 Category PACK This category summarizes all the options used by the sphere geometry optimization SGO algorithm In the atomic sphere approximation ASA space is divided in spheres centered at the atomic sites These spheres are required to fill space com pletely in order that the region between the spheres the socalled interstitial region vanishes However there exist crystal structures where the aforementioned condi tion would lead to rather large overlaps of the atomic spheres In that case usually socalled empty spheres are included which model the crystal potential in such large voids The SGO algorithm automatically finds optimal empty spheres positions and the best radii of all physical and empty spheres 4 9 1 Token FILLNG cast double This token specifies the fraction of space which eventually must be filled by the atomic spheres Default is FILLNG 1 0 The special setting FILLNG 0 0 enforces creation of touching spheres 4 9 2 Token OBYDMX cast double Maximum allowed overlap for any pair of spheres scaled to the distance between the sphere centers A good value is OBYDMX 0 15 which is the default For some systems it might be necessary to go beyond this value in order to achieve complete space filling However yo
90. ergy interval from 5 5 to 1 5 eV observations thus confirm our arguments put forward in the above discussion of the bare band structure and the partial densities of states Actually these orbital weighted band structures are a necessary prerequisite for a complete understanding of the electronic structure Yet only few band structure packages offer this analytical tool 2 1 5 Crystal orbital overlap population Another feature which is not standard in modern band structure codes is the im plementation of the crystal orbital overlap populations COOP The COOP as 24 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES 6 0 4 0 2 0 0 0 E 2 0 eV 10 0 W L X W K Figure 2 3 Weighted electronic structure of Cu The width of the bars given for each band indicates the contribution due to the 48 orbital 10 0 W Figure 2 4 Weighted electronic structure of Cu The width of the bars given for each band indicates the contribution due to the 4p orbitals 2 1 A SIMPLE CASE CU 25 6 0 4 0 2 0 0 0 SV mm 2 mm 4 0 I L Figure 2 5 Weighted electronic structure of Cu The width of the bars given for each band indicates the contribution due to the 34420 orbitals SV o 7 fiet HN 1 j i 10 0 W X W K Figure 2 6 Weighted electronic structure of Cu The width of the bars given for each band indicates the contribution due to the 3de orb
91. esent chapter we will discuss how the programs coming with the ASW distribution can be used In doing so we will apply the programs to two different examples namely FeS5 and 2 1 A simple case Cu Elemental copper has been used as a test case for electronic structure programs since long This is due to several reasons As we will learn below the electronic structure of this metal is strongly influenced by three groups of electrons While the core electrons are tightly bound to the nucleus and hence have a very high charge density at the center of the atom but an almost negligible density in the outer region the wave functions of the 4s and 4p electrons reach far out and spread even in the region of neighbouring atoms Finally the 3d electrons are somewhat intermediate in that they likewise contribute to the overlap with neighbouring atoms hence to the metallic bonding but still are rather well localized near the nuclei Since the 3d states of copper are almost filled they contribute only weakly to the Fermi surface which is therefore formed mostly by the 4s and 4p states As a consequence although the 3d states are found well below any changes or errors in the 4sp 3d overlap strongly affect the Fermi surface For this reason copper is regarded as a sensitive test case Calculated electronic structures for this material were compared to the results of photoemission experiments already in the early 1960 s by Burdick 17 T
92. et of atomic sites and to set up the remaining sites from the given symmetry operations Finally in case that both the complete set of atomic sites and the generators for all symmetry operations are given both are checked for consistency 4 8 1 Token GENPOS cast logical This switch indicates that the basis set of atomic positions is completed by using the minimal set of positions given in category SITE and the following generators of the full group of symmetry operations The default is GENPOS F 4 8 2 Token SYMOPS cast character length 48 Here you may specify generators for the full group of the symmetry operations These generators are most easily coded by using the following short hand notation and T denote unity operation and inversion while R 5 and M are short for proper and improper rotation respectively and reflection Finally T stands for a fractional translation following any of the just mentioned operations R must be followed by an integer denoting the angle of rotation as the number of division of the full circle Moreover Ri and must be followed by a vector a b c yielding the rotation axis the vector perpendicular to the mirror plane and the translation vector respectively The components a b and c of the vectors must be real numbers exceptions being the abbreviations C and 75 for 0 5 and 0 5 sqrt 3 respectively and 0 71 1 2 1 3 71 4 and
93. f the main programs Having run the packing program mnpac run we are able to run the self consistent field calculation just as in the case for Cu above To do so we copy file CNEW to CTRL and just type mnscf x or else mnall x depending on the amount of calculations to be performed Already after a few iteration susan outlst6 will tell us that the program found a finite indirect band gap which qualifies iron pyrite as an semiconductor Now it is time to browse the input Going to the end and searching backward for the string Fermi will put you on the top of a list containing for each class and partial wave angular momentum the amount of charge and the contribution to the density of states at Ep Of course for an insulator or semiconductor the second column contains only zeros Special attention deserves the first column If compared to the atomic configurations these partial occupations reflect the charge transfer between the orbitals If summed over all orbitals of an atom they give rise to the deviation from the neutrality of an atom which is given in an extra list above For most atoms the occupation of the orbital with highest angular momentum is quite small below 0 1 electron This guarantess convergence of angular momentum expansions of the wave functions In case the charge contained in the highest l state is above 0 1 warning is issued Values up to 0 13 are still acceptable otherwise value given by LMXL must be increased In contra
94. gnetic moments densities of states and the total energy and pressure program falls into two parts In band part calculated intraatomic matrix elements are used to set up the secular matrix From solving the corresponding eigenvalue problem eigenvalues and eigenvectors are obtained and the respective contributions added to the partial densities of states This process is repeated for all k points in the irreducible wedge of the first Brillouin zone Finally from the partial densities of states the partial charges and magnetic moments as well as the first four moments of the partial DOS are constructed The latter could be translated into energies hence boundary conditions for the intraatomic wave functions The band part usually takes more than 95 of the execution time of the program Note that in during this time no files are read or written Hence if you want to stop the program for whatever reason without loosing the atomic files you should do it during the band part 3 1 MAIN PROGRAMS AND SHELLSCRIPTS 69 In the atomic part the partial charges and boundary conditions logarithmic derivatives provided by the band part are used to calculate the intraatomic wave functions and from this the intraatomic charge density Within the notions of den sity functional theory and the local density approximation the latter gives rise to the effective potential and total energy Finally the potential enters a radial Schr dinger equation leading
95. gth 3 First plot vector specifying the plot space Default is RPLOT1 0 0 0 0 0 0 4 16 4 Token RPLOT2 cast double length 3 Second plot vector specifying the plot space Default is RPLOT2 0 0 0 0 0 0 4 16 5 Token RPLOT3 cast double length 3 Third plot vector specifying the plot space Default is RPLOT3 0 0 0 0 0 0 4 16 6 Token NPDIV1 cast integer Number of divisions along the first plot vector Default is NPDIV1 50 4 16 CATEGORY PLOT 113 4 16 7 Token NPDIV2 cast integer Number of divisions along the first plot vector Default is NPDIV2 50 4 16 8 Token NPDIV3 cast integer Number of divisions along the first plot vector Default is NPDIV3 50 114 CHAPTER 4 THE MAIN INPUT FILE CTRL Chapter 5 The ASW database Over the years I have many people using the ASW method have contributed to what is now called the ASW database It consists of a large number of CTRL files for various elemental systems and compounds The complete list is given below List of CTRL files contained in the ASW database status as of 11 03 2002 CTRL Ag CTRL AgBr CTRL AgEr CTRL AgI CTRL 1 CTRL A1203 Nb8 CTRL 1 CTRL A1Mo484fcc CTRL A1Mo484tri CTRL A1Mo484trife CTRL_A1Mo4S4triid CTRL_A1P CTRL_A1Sb CTRL_Ar CTRL_Au CTRL_AuZn3 CTRL_B203 CTRL_BN CTRL_Ba CTRL_BaA110Mg017 CTRL_BaB204 CTRL_BaGa204 CTRL BaNi03 CTRL 0 CTRL BaUn CTRL BaTi03 CTRL BaVS3hex CTRL Be CTRL 0 556 e
96. hat two changes have to be made First in order to take advantage of the spin sublattice symmetry coming with antiferromagnetic order we insert the token AFSYM T into the category OPTIONS Second in order that the program can detect the particular antiferromagnetic order each atomic site has to desginated as spin up or spin down This is achieved by the tokens SPIN to be appended to each atomic position in category SITE The updated category will look like the following SITE CARTP F ATOM CR POS 0 000000 0 000000 000000 SPIN UP ATOM CR POS 0 500000 0 500000 500000 SPIN DN ATOM 0 POS 0 302400 0 ATOM 0 POS 0 302400 0 302400 000000 SPIN UP ATOM 0 POS 0 197600 0 197600 500000 SPIN DN ATOM 0 POS 0 197600 0 197600 500000 SPIN DN ATOM E1 POS 0 000000 0 500000 0 250000 SPIN DN ATOM E1 POS 0 000000 0 500000 0 250000 SPIN UP 1 POS 0 500000 0 000000 0 250000 SPIN DN ATOM E1 POS 0 500000 0 000000 0 250000 SPIN UP 2 05 0 176474 0 176474 0 500000 SPIN DN 2 05 0 176474 0 176474 0 500000 SPIN DN 2 05 0 323526 0 323526 0 000000 SPIN UP 2 05 0 323526 0 323526 0 000000 SPIN UP 05 0 218838 0 411732 0 355939 SPIN DN 05 0 218838 0 411732 0 355939 SPIN DN P08 0 281162 0 088268 0 144061 SPIN UP 05 0 281162 0 088268 0 144061 SPIN UP 05 0 411732 0 218838 0 355939 SPIN DN 05
97. he Cr 3d states Yet as already mentioned above the standard axes of the local octahedra differ from the Cartesian coodinate system used to specify the primitive translations For this reason a transformation of the coordinate system has to be performed before the projected densities of states can be plotted This is achieved by specifying the correct rotation in the following dialog 46 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES 2 E 6 DOS 1 eV Figure 2 17 Partial densities of states DOS of CrO per formula unit ASW 1 9 program PLDOS started on majestix at Thu 14 Mar 2002 15 00 25 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details All input will be echoed to file PLID Enter terminal type 1 X Windows default 2 PC Screen vt220 emulation 3 suppress terminal output Enter output device Postscript default Color postscript LaTeX LaTeX VE s way HP LaserJet III PCL5 HP LaserJet II GIF leave the decision for later suppress output to file KE Enter title Energies in Rydberg f or eV t default DOS scaled accordingly Energies relative to MTZ 0 or EFermi F default Portrait P default landscape L or encapsulated postscript plot E Energy axis to the top f or right t default 2 3 A MAGNETIC SYSTEM CRO 47 Plot DOS f default or integrated DO
98. he following calculations proceed in several steps First we have to set up the CTRL file which is the only input file for the calculations other files needed during the execution of the programs are created automatically and they are deleted in case the program does not need them any more Once the self consistent calculation has converged additional main programs may be invoked to evaluate the band structure or the partial DOS Finally the plot programs can be used to visualize the results 11 12 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES 2 1 1 CTRL file Let us start out by listing a minimal CTRL file for Cu HEADER Cu fcc data by Landolt Bernstein VERSION ASW 2 0 STRUC 6 83079 SLAT FCC CLASS 2 29 SITE ATOM CU POS 0 0 0 0 0 0 Each CTRL file is grouped into categories which begin with a keyword at the beginning of a line In the listing five categories are identified namely HEADER VERSION STRUC CLASS and SITE Each category comprises additional in formation which except for the first two categories is passed to the program by socalled tokens They have the form TOKEN followed by one or more integers real numbers strings or switches T or F To be specific in the present example the category STRUC contains all information about the Bravais lattice in form of the lattice constant ALAT 6 83079 and the Bravais lattice type SLAT FCC face centered cubic While this fixes the unit ce
99. he mantissa xeps 2 22044604925031D 16 min such that 1 0 xeps gt 1 0 xepsn 1 11022302462516D 16 min such that 1 0 xepsn 1 0 minexp 1021 min exponent before gradual underflow xzer 2 22507385850720 308 underflow threshold base minexp 1 xmin 2 22507385850720 308 safe min 1 xmin does not overflow maxexp 1024 largest exponent before overflow xinf 1 79769313486232 308 overflow threshold base maxexp 1 xepsn irnd 1 0 1 for chopping rounding in addition task 1 total cpu time 0 00000 sec ASW 1 9 program MNMPR ended on majestix at Fri 11 Jan 2002 08 31 10 This toy program mainly serves the purpose of checking the compiler and ma chine capabilities 3 1 2 mnhlp x In order to summarize the way most of the shellscripts work I have created this file which is a fully commented version of the shellscript mnmpr x bin sh Command file mnhlp x for queuing a batch job executing an ASW program This file serves as a commented example file for all the other shell scripts The script is prepared for use with the LoadLeveler LoadL the Network Queuing System NQS the Portable Batch System PBS the Distributed Queuing System DQS and Sun s Grid Engine SGE Please adapt to your own environment and needs Version ASW 1 9 29 09 2003 Volker
100. hich contains an updated version of the CTRL file 3 1 4 mnfre run mnfre x This program performs a free atom calculation for each atomic class in the unit cell and generates a first guess to the full charge density and potential from the superposition of the respective free atom quantities This usually goes under the name Mattheiss construction The calculation is done for points along a line or lying within a plane as defined by tokens ORIGIN RPLOT1 and RPLOT2 depend ing on the number specified by tokens NPDIV1 and NPDIV2 Set NPDIV2 0 to enforce a line plot The result is written to file FREE and can be plotted using plfre run or plfre x 3 1 5 mnovl x An overlap check of all atomic spheres can be performed using this shellscript which calls mnfre run but stops after the overlap check The result is printed to file outovl which lists the overlap limits the positions and radii of all atomic spheres In addi tion a full list of pairs of atoms their distance and their overlap is given together 68 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE with exclamation marks pointing to large overlaps number of entries in the list can be controlled by token VERBOS With the default setting VERBOS 30 only pairs with a nonvanishing overlap are included 3 1 6 mnpac run mnpac x In order to invoke the sphere packing using the sphere geometry optimization algo rithm you have to call this program In a first part free atom
101. hors their worked was based on the concept of renormalized atom calculations as proposed by Watson Ehrenreich Hodges and Gelatt 13 12 11 and inspired by the ideas of the linear methods as presented by O K Andersen 14 In the eighties the ASW program saw several revisions and extensions mainly done by the Darmstadt group of J K bler These included the development of a version for treating non collinear spin arrangements 8 9 as well as the implemen tation of a first full potential ASW method by myself 1 In addition J Sticht and I put a lot effort in tuning the program to optimal performance especially for vector machines Commercializing the code set in by the end of the eighties when the California based software company BIOSYM later Materials Science Incorporation MSI now Accelrys started distribution of the standard Darmstadt code Nevertheless the old Darmstadt version still suffered from many drawbacks Programming was completely done in a rather old fashioned Fortran77 style using e g variables and arrays of mixed accuracy File handling was quite complicated and reading from the input files was done in fixed format In the startup phase of a calculation several different programs and input files had to be used All this made the program rather user unfriendly and error prone In order to overcome these difficulties of the old Darmstadt version I started a completely new implementation of the code Programming was d
102. i blue 2 dashed2 red 3 dotted magenta 4 dashdottedi cyan dashdotted2 yellow 6 chaindashed1 black 7 chaindashed3 gray 9 chaindashed2 coral 8 Enter curve label to Cu 3d t 2g suppress Please wait a moment I m working on this curve Set up more curves t Default is f t Start setting up curve 4 Plot partial f or total DOS t default 19 3x 2y y 3 x 2z y 2z 3 A marks styles already selected 20 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default E Enter orbital s to be included Class CU atom i at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 3 all f 1 s 2 y 3 2 4 x 5 Xy 6 yz 7 3z 2 r 2 8 2 9 x 2 y 2 10 3x 2y y 3 11 xyz 12 5yz 2 yr 2 13 5273 32 72 14 5xz 2 xr 2 15 x 2z y 2z 16 x 3 3xy 2 7 9 The following orbitals have been selected Class CU atom 1 orbital 3z 2 r 2 Class CU atom 1 orbital x 2 y 2 Enter scaling factor default 1 0 Broadening of this curve t or not f default Select curve style default 4 A marks styles already selected solid green 1 dashedi blue 2 dashed2 red 3 dotted magenta 4 5 dashdottedi cyan 5 dashdotted2 yellow 6 2 chaindashed1 black 7 chaindashed2 coral 8 A
103. iS CTRL_NiS2 CTRL_NiS2af CTRL_NiSe2 CTRL_NiTi CTRL_Nibcc CTRL_NpB2 CTRL_Os CTRL_P205 CTRL_Pb CTRL_PbBiCuS3 CTRL_PbO2 CTRL_Pd CTRL_Pr CTRL_Pt CTRL_Pu CTRL_Rb CTRL_Rb7Nal6Sb7 CTRL_Re CTRL_Rh CTRL_Ru CTRL_Ru2Si3 CTRL_Ru4Se4 C0 12 CTRL Ru48e4 CO 12dis CTRL Ru48e4 C0 1214 Ru48e4 C0 12idtri CTRL Ru48e4 CO 12tri CTRL Ru6C CO 17 CTRL CTRL_Ru02 CTRL RuOC10H16 CTRL_RuS2 CTRL_WA13 CTRL_WS2 2H CTRL_WS2 2Hd1 CTRL WS2 2Hs1 CTRL WSe2 2H CTRL WTe2 1T WTe2 2H CTRL WTe2 Td Xe CTRL Y CTRL_Y202S CTRL_Y203 Y3Co4Ge7 YA12 CTRL_YBO3 CTRL_YBO3hex CTRL_YBa2Cu307 CTRL YCu02 YIr28i2bct CTRL_YIr2Si2st CTRL_Yb YbA13 CTRL YbCo2Ge2 CTRL_YbCu4Au CTRL_YbCu4Pd CTRL_Zn CTRL_ZnGa204 CTRL_ZnO CTRL_ZnS CTRL_ZnS2 CTRL_ZnSbct CTRL_ZnSdfcc CTRL_ZnSdfccsi CTRL_ZnSdfccs2 CTRL_ZnSdsc CTRL ZnSdscs1 CTRL_ZnSe CTRL_ZnSsc CTRL_ZnSscs1 CTRL_Zr CTRL_ZrA12 CTRL_ZrCo2 CTRL_ZrCr2cub CTRL_ZrCr2hex CTRL_ZrFe2 CTRL_ZrMn2 CTRL_ZrMo2 CTRL ZrV2 CTRL ZrW2 CTRL In203s2 CTRL_RuSe2 CTRL_InAs CTRL_Sc CTRL_InP CTRL_ScA12 CTRL_InSb CTRL_Si CTRL_Infcc CTRL_Si46 CTRL_Ir CTRL_SiA13 CTRL_Ir02 CTRL_Si02 CTRL_K CTRL_SmA13 CTRL_K2CuF4bct CTRL_SmB6 CTRL_K2CuF4sco CTRL_SmS 119 CTRL_ZrZn2 CTRL_ BEDT TTF 213 CTRL VO 962Cr0 038 203 CTRL VO 990Cr0 010 203a CTRL VO 990Cr0 010 203b CTRL VO 2P207 CTRL_ V0 2P207hp CTRL
104. ich contains all the eigenvectors Next you invoke again the plotting shellscript plbnd x and enter the following dialog ASW 1 9 program PLBND started on majestix at Fri 08 Mar 2002 21 26 15 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details All input will be echoed to file PLIB Enter terminal type 1 X Windows default 2 PC Screen vt220 emulation suppress terminal output Enter output device Postscript default Color postscript LaTeX LaTeX VE s way HP LaserJet III PCL5 HP LaserJet II GIF leave the decision for later suppress output to file AUNE 4 Enter title Energies in Rydberg f or eV t default Energies relative to MTZ 0 or EFermi F default Portrait P default or landscape plot L Energies connected by lines t default f Plot orbital character default f t For plotting orbital character Rotate reference frame for orbitals Enter rotation symbol E for unity Enter orbital s to be included Class CU atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 2 1 A SIMPLE CASE CU 23 1 s 2 y 3 2 4 x 6 2 7 3z 2 r 2 8 2 9 x 2 y 2 The following orbitals have been selected Class CU atom 1 orbital s Please wait a moment I m reading the bands Timing for 19 points out of 199 0 00000 sec Ebot 9
105. ich contains the ratio c a of the tetragonal lattice constants Alternatively we could have inserted the lattice con stant c directly by the token CLAT In particular for non cubic crystal structures it is useful to specify the atomic positions in terms of the primitive translations which could be non orthogonal or of unequal length rather than the Cartesian coordinate system scaled by the lattice constant a The corresponding switch is covered by the token CARTP F As a consequence the last component of the second chromium site as well as half of the oxygen sites is given by 0 5 rather than 0 32979 As for iron pyrite the openness of the rutile structure requires to insert empty spheres Again this is done by executing mnpac x It produces file CNEW which deviates from the above CTRL file by the categories CLASS and SITE updated as follows CLASS 2 24 R RA 2 14485 LMXL 2 CONF 4 4 3 4 QVAL 1 0 0 0 5 0 0 0 0 Z 8 R RA 1 83785 LMXL 1 CONF 2 2 3 QVAL 2 0 4 0 0 0 ATOM E1 Z 0 R RA 1 65282 LMXL 1 CONF 1 2 3 QVAL 0 0 0 0 0 0 ATOM E2 Z 0 R RA 1 76299 LMXL 1 CONF 1 2 3 QVAL 0 0 0 0 0 0 ATOM E3 Z 0 R RA 0 77096 LMXL 0 CONF 1 2 QVAL 0 0 0 0 SITE CARTP F ATOM CR 05 0 000000 0 000000 0 000000 ATOM CR POS 0 500000 0 500000 0 500000 ATOM 0 POS 0 302400 0 302400 0 000000 0 P08 0 302400 0 302400 0 000000 0 POS 0 197600 0 197600 0 500000 0 POS 0 197600 0 197600 0 500000
106. ies near future forces structure optimization near future e Chemical Bonding total partial crystal orbital overlap population COOP total partial crystal orbital Hamiltonian population COHP total partial covalence energy Ec e Magnetic Properties total and site state projected magnetic moments magnetic ordering ferro ferri antiferromagnetic magnetic energy gains spin densities near future spin densities at the nuclei hyperfine fields Suggestions for additional properties which should be implemented are always wel come Just sent an email to the address given above 1 3 PROGRAMMING 5 1 3 Programming At present the ASW program package consists of 2 100000 lines of source code which are organized in a dozen main programs and about 400 subroutines While the first versions were written in Fortran77 the latest version has been fully adapted to the new Fortran95 standard In particular dynamic memory now makes the package much faster and more flexible than before Moreover switching to Fortran95 has enhanced portability of the code considerably In setting up the program I have much benefitted from ftnchek which is a public domain tool for syntax checking of Fortran programs Among other things it pro vides means to check data exchange between the main program and subroutines which usually is note done by a compiler I higly recommend ftnchek to any Fortran programmer As i
107. ile is common to all main programs and contains parameters which con trol the size of many arrays Please check the maximum number of interstitial energies kappa values keep 1 if you are in doubt and the maximum number of atoms Again this step can be skipped in the first installation 4 Type make all This step which alternatively can be performed as background procedure by invoking the shell script mkall x generates all executables Due to the many new features incorporated in the Makefile its execution might require GNU make which is free software and available from many servers e g www gnu org 1 5 LINKING WITH OTHER SOFTWARE T 5 Type make install This copies all executables shell scripts and IXTEXenvelope files to the direc tory specified in step 1 above 1 5 Linking with other software There are some public domain software packages used by the ASW software namely BLAS ATLAS LAPACK GNUPLOT RasMol XMakeMol and ftnchek which are all public domain However all BLAS ATLAS and LAPACK routines needed by the ASW software are already included in the ASW package So you don t need to transfer extra files 1 6 Legal matters Since the ASW program package is commercially distributed legal matters have to be considered Most of this is contained in the file COPYRIGHT coming with the distribution which is printed here for completeness
108. ime being we turn again to the orbital weighted band structures The results shown in Fig 2 14 clearly confirm the observation made in the partial FeS2 sc w Fe 3d FeS2 sc w 5 3p Figure 2 14 Weighted electronic bands of 52 The width of the bars given for each band indicates the contribution due to the a Fe 3d and b S 3p orbitals respectively DOS that the upper valence band as well as the lower half of the conduction band 40 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES group trace back to the Fe 3d states while the upper half of the conduction band is more 5 like Yet the lowest edge of the conduction band near the is almost exclusively due to the S 3p orbitals and explains the sensitivity of the optical band gap to the bond length within the sulfur pair as found in Ref 23 2 3 A magnetic system CrO Apart from the elemental magnets Fe Co Ni and Gd chromium dioxide probably belongs to the most wellknown ferromagnetic metals Of course this traces back to its applicability as a material for magnetic recording tapes which is a consequence of the high Curie point of 391K well above room temperature Additional interest in this compound stems from the fact that in general the transition metal dioxides comprise the largest class of oxides with a similar struc ture and showing a large variety of physical properties As is obvious from Tab 2
109. in degenerate case Sec 2 3 2 However since you have only copied the CTRL file to the new directory the program mnscf run will start the spin polarized calcula tions from scratch An alternative and very elegant way consists of also copying the atomic files of the converged non magnetic calculations Now invoking mnall x lets the program mnscf run which is the first program called from the shellscript mnall x detect the preconverged files As already outlined in Sec 2 1 this will invoke the restart facility of the program During this startup phase the information from the converged spin degenerate calculations is combined with the starting values for the magnetic moments per orbital as given in the CTRL file in order to find an optimal starting point for the spin polarized calculation As a consequence very fast iteration to full self consistency is achieved After convergence susan outlst30 summarizes the results as follows ASW 1 9 program MNSCF started on majestix at Sat 09 Mar 2002 16 19 41 Calculation converged after 7 iteration s Start of Iteration 7 1800 irreducible k points generated from 27000 30 30 30 Fermi energy MTZ 0 737422 Ryd 2 8 MAGNETIC SYSTEM CRO 57 Indirect band 0 140526 Ryd 1 911955 eV DOS at Fermi energy 38 499331 1 Ryd Magnetic moment of unit cell 4 000000 Mean square residual 0 370346D 13 Madelung energy 3 760944 Zeeman energy 0 000000 total 3pV 0 204459 virial energy
110. in the CTRL file Just add in category CLASS the token COORB followed by the angular momenta of the orbitals you want to be considered In the present case we have added COORB 0 12 Furthermore we inserted the entry SAVCOOP F in category BZSMP Cal culation is then invoked by typing mndos x at the systems prompt Within this shellscript the setting SAVCOOP F is automatically changed Alternatively you could specify the tokens COORB at the very beginning before the self consistent calculations start and then invoke the shellscript mnall x which likewise includes calculation of the It generates a new file named In order to plot the results just type plcop x and answer the prompts of the program in close accordance with those required by the plotting routine for the DOS However note that for each 2 1 SIMPLE CASE CU 27 curve two orbitals are required 2 1 6 Fermi surface In closing this section we take up the discussion at the beginning and display in Fig 2 8 the Fermi surface of Cu as measured by photoelectron spectroscopy and Cu 001 ntensi E 1 A Figure 2 8 Measured and calculated Fermi surfaces of Cu 22 calculated by the ASW method 22 The agreement between both data is clearly 28 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES visible Unfortunetely the calculation of Fermi surfaces is not yet fully implemented in the code and thus not generally available 2 2 more
111. ion acceleration e and convergence criteria files following in the present list are automatically created and deleted by the programs complete description of the CTRL file and all its categories and tokens is given in Chap 4 3 4 6 CBAK the main programs except for mnmpr run write an updated copy of the CTRL file to file CBAK unless a different name is specified by token WRITE in category IO 3 4 7 CNEW The packing program mnpac run writes a new CTRL file named CNEW remember file CTRL is never written to which includes possibly created empty sphere posi tions as well as the radii of all spheres Before proceeding with the self consistent calculations you must rename the file CNEW to CTRL 3 4 8 HELP A first overview over the capabilities of the ASW program package can be best obtained by creating the HELP file In case this is missing in the distribution it can be most easily obtained by writing the line IO HELP T 6 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE to the CTRL and running any of the ASW main programs those starting with This will generate the HELP file listed here HELP fi categor title categor token categor token token token token token token token categor token token token token token token token token token token token categor token le for ASW 1 9 y HEADER y VERSION ASW of cast doub
112. ital 26 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES originally proposed by Hoffmann allows for an analysis of the chemical bonding 18 Evaluation of the COOP has been recently implemented in the ASW method 19 see also Refs 3 20 and was successfully applied to the interpretation of bonding properties of various compounds 3 Very recently F hnle and coworkers developed an extension of the COOP the socalled covalence energy 21 which we have also implemented in the ASW package The result for Cu is shown in Fig 2 7 There Cu 4sp 4sp Cu 4sp 3d Cu 3d 3d ECOV E Eg eV Figure 2 7 Partial covalence energies of Cu we observe three curves which are energy resolved measures of the chemical bond ing between the respective orbitals Negative and positive contributions indicate bonding and antibonding states respectively While the 4sp 4sp bonding is almost negligible the bonding between 4sp and 3d states as well as the 3d 3d bonding is clearly visible Both are bonding below 2 2 eV and antibonding above Since the 3d 3d antibonding behaviour dominates we can conclude that the metallic bonding hence crystal stability is carried to a large part by the 4sp 3d bonding Calculation of the crystal orbital overlap population or else the covalence energy is done in the same step as the calculation of the partial DOS In order to obtain these curves you have to specify the respective orbitals
113. ith the exception of mnmpr run start reading the CTRL file As has been already outlined in Sec 2 1 the ASW program package includes both the executables with ending run and corresponding shellscripts with ending x The latter call the executables and specify the respective output files In addition the shellscripts provide commands for the most common batch queuing systems as IBM s LoadLeveler LoadL Network Queuing System NQS and the public domain packages Portable Batch System PBS Distributed Queuing System DQS as well as Sun s Grid Engine SGE Finally some of the shellscripts include appropriate modifications of the CTRL file A fully commented example shellscript is contained in the file mnhlp x which should be consulted for more information In the following discussion we will use the names program executable and shellscript synonymously 3 1 1 mnmpr run mnmpr x While all main programs calculate the parameters of the actual machine at the very beginning this program prints them out and stops The output usually looks like file MACH coming with the distribution ASW 1 9 program MNMPR started on majestix at Fri 11 Jan 2002 08 31 10 63 64 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details Machine specific parameters affecting floating point arithmethic ibase 2 base of the machine it 53 number of base digits in t
114. itten by an elder version release where some tokens had been in other categories as they are in version 1 9 By specifying the correct version you can take advantage of the upward compatibility of the package 4 3 Category IO This category contains specifications about which and how much information the programs should write to output as well as to the atomic files 4 3 CATEGORY IO 89 4 3 1 Token HELP cast logical This logical switch allows to print out the HELP file as listed in Sec 3 4 which comprises a short hand version of this chapter Default is HELP F To create the HELP file HELP T and run any of the main programs those starting with mn be specific create a CTRL file containing the lines VERSION ASW 1 8 IO HELP T and write mnscf x at the operating system s prompt In addition to the HELP file the program produces an output file called outscf which mainly contains a full CTRL file comprising all categories and tokens with their default values 4 3 2 Token SHOW cast logical If set to true this token makes the program echo the CT RL file to the output This mode is highly recommended since it allows you to check the input for the calculation lateron In addition as an extra bonus whenever you have lost the CTRL file you may easily recover it just by cutting the respective portion out of the output For these reasons the default is SHOW T 4 3 3 Token VERBOS cast integer Here
115. l allow for a discussion in terms of the latter There exist two different metal oxygen distances namely the apical distance which is between metal and oxygen atoms having the same z value and the equatorial distance between the metal atom and the four neighbouring ligand atoms with 2 20 1 2 3 As has been already indicated in Fig 2 15 it is useful to discuss the electronic structure of rutile type compounds in terms of local coordinate systems centered at each metal site Note that due to the different orientation of octahedra centered at the corner and the center of the rutile cell the local z axes point alternately along the 110 and 110 direction In contrast to the usual adjustment of the x and y axes parallel to the metal ligand bonds we have rotated these axes by 45 about the local z axes such that they are parallel and perpendicular respectively to the rutile axis With the previous choice of local coordinate systems the e states resulting from the cubic part of the crystal field splitting of the metal d orbitals comprise the d3 2_ 2 and dz orbitals whereas the tg states are made of the 2 2 dez and dy orbitals While the d 2_ 2 orbitals point along the rutile c and the local y axes i e towards the edges of the basal plane of the octahedron the d and d orbitals are directed towards the faces 2 3 1 CTRL file and sphere packing the previous informations have been condensed into the following CTRL file
116. l be needed for full convergence at the higher k space grid Such stepwise increase of the Brillouin zone density serves the additional purpose that on comparing the results we are able to check convergence of the result with respect to the fineness of the k point grid The results of all these calculations are stored in the files outlst6 to outlst30 Finally the band structure and the partial densities of states are calculated In order to have quick check of the progress of a self consistent calculation just type e g susan outlst30 which will write the following lines to screen ASW 1 9 program MNSCF started on majestix at Fri 08 Mar 2002 14 14 02 Calculation converged after 5 iteration s Start of Iteration 5 2480 irreducible k points generated from 27000 30 30 30 Fermi energy MTZ 0 641842 Ryd DOS at Fermi energy 3 084967 1 Ryd Mean square residual 0 184027D 14 Madelung energy 0 000000 Zeeman energy 0 000000 total 3pV 0 170258 virial energy 3304 885873 variational energy 3304 885885 qdiff 0 00000000 lt 0 00000001 ediff 0 00000000 0 00000001 ASW 1 9 program MNSCF ended on majestix at Fri 08 Mar 2002 14 14 14 They include information about the k space grid the position of the Fermi en ergy the DOS at Ep the variational total energy and the self consistency level already reached as coded by the entries qdiff and ediff 2 1 SIMPLE CASE CU 15 2 1 3 Execution of the plot programs
117. la tions which start from moments of the densities of states and make available the intraatomic matrix elements entering the Hamiltonian matrix run through an in traatomic self consistency cycle During this intraatomic iteration the intraatomic charge density and potential are made self consistent while preserving the moments of the partial DOS Note that the following band iteration might result in different moments hence intraatomic self consistency does not mean full self consistency of the whole crystal In contrast to token NITBND above token NITATM specifies the number of intraatomic iterations The default value is NITATM 50 which hardly needs a change Note that the contribution of the intraatomic calculations to the total execution time is negligible 4 12 8 Token CNVGQA cast double This token fixes the desired accuracy of the intraatomic calculations Once this value has achieved the intraatomic self consistency cycle stops In particular CNVGQA is the accuracy for the root mean square difference of the intraatomic charge density resulting from the previous and the present intraatomic iteration The default value is CNVG 1 0D 10 which is very accurate However due to the very low execution time of the intraatomic calculations and the speedup of the expensive band iterations by accurate atoms this value is well justified and needs no changes 108 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 13 Category MIXING This categ
118. le Version release of program which has written CTRL y IO HELP of cast logical Switch to print HELP file SHOW of cast logical Switch to echo CTRL file to output VERBOS of cast integer Verbosity level for printing of output IACTIV of cast logical Switch to start interactive mode CLEAN of cast logical Switch to shrink atomic files after convergence WRITE of cast character Name of file to which a copy of CTRL file is written EXTENS of cast character Default extension for all files besides CTRL file y OPTIONS REL of cast logical Switch to scalar relativistic mode LSCPL of cast logical Switch to turn on LS coupling NSPIN of cast integer Number of spin channels AFSYM of cast logical Switch to use antiferromagnetic symmetry if present BEXT of cast double External magnetic field in z direction XCPAR of cast character String for XC parametrization GGA of cast character String for GGA parametrization OVLCHK of cast logical Switch to perform overlap check CCOR of cast logical Switch to use combined correction to the ASA FULPOT of cast logical Switch to full potential calculation CORDRD of cast logical Switch to frozen core calculations y STRUC mandatory UNITS of cast character 3 4 DATA FILES TT token token token token token token token token Units to be used in STRUC and SUPCELL ALAT of cast double mandatory Lattice constant A in UNITS PLAT of cast
119. lected Class CR atom 1 orbital xy Class CR atom 1 orbital 3z 2 r 2 Enter scaling factor default 1 0 Broadening of this curve t or not f default 2 3 A MAGNETIC SYSTEM CRO 49 Select curve style default 2 A marks styles already selected solid green 1 dashedi blue 2 dashed2 red 3 dotted magenta 4 3 dashdottedi cyan 5 dashdotted2 yellow 6 chaindashedi black 7 chaindashed2 coral 8 chaindashed3 gray 9 Enter curve label to suppress Cr 3d e g Please wait a moment I m working on this curve Set up more curves t Default is f T Start setting up curve 3 Plot partial f or total DOS t default F For partial DOS Rotate reference frame for orbitals Enter rotation symbol Default R8 1 1 0 R4 1 1 0 Enter orbital s to be included Note notation of the orbitals refers to the rotated reference frame Select from the classes blank or to complete the list CR 0 1 2 0 Class 0 atom 3 at 0 302400 0 302400 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 1 s 2 3 2 4 x 5 Xy 6 yz T 3z 2 r 2 8 xz 9 x 2 y 2 1 0 atom 4 at 0 302400 0 302400 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 1 s 2 3 2 4 X xy 6 yz 7 3z 2 r 2 8 2 9 x 2 y 2 1 Class 0 atom 5 at 0 197600 0 197600 0 329790 Select from the following orbitals 0
120. linear radii scaling R or linear volume scaling V R Enter scale factor 0 100 1 342 default 1 000 0 6 The plot space contains 1 unit cell s Enter strings for rotations Default strings are rotate x 90 rotate y 5 34 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES rotate x 10 Overwrite or enter when you re done task 1 total cpu time 0 00000 sec ASW 2 0 program PLSTR ended on majestix at Mon 11 Mar 2002 12 38 05 At the end the shellscript will automatically ask you for calling either RasMol or XMakemol and display a picture of the crystal structure similar to the one shown in Fig 2 9 All your input to the plot routine plstr run will be echoed to file PLIS In case you have already run through the SGO algorithm and just want to create a new plot of the crystal structure type mnstr x This shell script will likewise call program mnpac run but by changing token QUIT to QUIT STR will stop execution after file STRU has been written In addition to generating this file program mnpac run will write a new version of the CTRL file to file CNEW which contains all the empty sphere positions as well as atomic sphere radii of all atoms Recall that the programs never write to file CTRL Finally mnpac run proposes the number of partial waves to be included by the tokens LMXL and CONF These two tokens have been set quite conservatively and might need an adjustment the subsequent self consistent field
121. ll be needed if a cal culation starts from scratch As for the previous tokens this input can be uniquely derived from the atomic number 4 6 11 Token MVAL cast double length 4 Here you can give starting values for the magnetic moments of the valence states to be used for starting a spinpolarized calculation These moments arise as the difference of the spin up and spin down partial charges Reasonable default values for each atom are proposed by the program 4 7 Category SITE mandatory Finally the structural information os completed by specifying the atomic sites in this category 48 CATEGORY SYMGRP 97 4 7 1 Token NBAS cast integer This token allows to specify the total number of atomic sites irrespective of the atomic species class The default value is 1 However note that this token needs not to be given since the number of sites is counted by the program as the number of POS entries see below Otherwise for token NBAS the same holds as was already said for token NCLASS above 4 7 2 Token CARTP cast logical This switch specifies whether the following entries for the atomic positions are in terpreted as Cartesian coordinates CARTP T or as relative components in terms of the primitive translations CARTP F The default value is CARTP T 4 7 3 Token CHOUT cast logical Sometimes it is useful to change the representation of the atomic positions from Cartesian coordinates to relative components or vice
122. ll of the crystal information about the geometry inside the unit cell is contained in the category SITE which gives the positions of all atoms In the present case only one atom exists which is located at the origin This atom is labelled by ATOM CU Finally the type of the atom located at the origin has to be specified This is done in category CLASS where the atom at the origin via its label is assigned the atomic number 29 Note that the label CU could be replaced by anything else However the program assumes that labels will not exceed six characters Finally the category HEADER holds space for up to 20 lines of text for user com ments However note that the first line the one containing the keyword HEADER is exceptional as its entry by default is used as a title line for all plots Last not least category VERSION specfies the program version to be used While the above CTRL file already allows for a complete calculation the standard CTRL file looks like the following HEADER Cu fcc data by Landolt Bernstein VERSION ASW 2 0 IO HELP F SHOW T VERBOS 30 CLEAN T OPTIONS REL T OVLCHK T STRUC ALAT 6 83079 SLAT FCC CLASS 2 29 R RA 2 66945 LMXL 2 CONF 4 4 3 4 QVAL 1 0 0 0 10 0 0 0 SITE ATOM CU POS 0 0 0 0 0 0 SYMGRP ENVEL 0 015 BZSMP 6 0 0 BZINT SMS EMIN 1 0 EMAX 1 5 NDOS 1000 NORD 5 WIDTH 0 02 EFTOL 1 0D 04 SAVDOS F CONTROL START QUIT FREE F NITBND 99 CNVG 1 0D 08 CNVGET 1 0D 08 NIT
123. lthough it is possible to start with the spin polarized calculations right away it is recommended to do the calculations for the spin degenerate case in ad vance First these calculations need half the execution time since the secular matrix has to be constructed and solved for only one spin direction Owing to the restart facility of the ASW program mnscf run the subsequent spin polarized calculations can start away with the converged files of the spin degenerate calculations rather then starting from scratch Second the result for the spin degenerate case establish a reference to which the results of the spin polarized calculation can be compared In particular by checking the total energies we are able find out the relative stability of the ferromagnetic state After convergence has been achieved susan outlst30 summarizes the results as follows ASW 1 9 program MNSCF started on obelix at Sat 09 Mar 2002 16 10 19 Calculation converged after 6 iteration s Start of Iteration 6 1800 irreducible k points generated from 27000 30 30 30 Fermi energy MTZ 0 752253 Ryd DOS at Fermi energy 103 450981 1 Ryd Mean square residual 0 546051D 12 Madelung energy 3 742272 Zeeman energy 0 000000 total 3pV 0 706054 virial energy 4794 027844 variational energy 4794 027883 qdiff 0 00000000 lt 0 00000001 2 8 MAGNETIC SYSTEM CRO 45 ediff 0 00000001 0 00000001 ASW 1 9 program MNSCF ended on obelix at Sat 09
124. m detects converged files but the CTRL files would require a start from scratch by the setting START REN the program stops in order not to overwrite the atomic files Finally if a spin polarized calculation finds converged spin degenerate files starting values for the intraatomic magnetic moments are imposed and the program enters a restart calculation Please see Sec 2 3 and Chap 4 for more detailed information 3 4 10 FREE The information about the overlapping free atom charge densities and potentials as created by program mnfre run go into this file It is formatted file hence it is written in ASCII 3 4 11 STRU This formatted file is written by programs mnfre run and mnpac run and contains the positions and muffin tin radii of all atoms with the plot region specified in the CTRL file 84 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE 3 4 12 MIX This file holds all information about the previous and the present band iterations to be used during the self consistency cycle It is automatically created by program mnscf run and after convergence has been achieved it is deleted However in case you stop the program and restart after a change of orbitals as described in Sec 2 2 2 this file must be deleted Note that MIX is an unformatted file 3 4 13 BNDE The formatted file BNDE contains the band structure E k as calculated as calcu lated by program mnbnd run 3 4 14 BNDV If required according to token ORBWGT T
125. mmended APPLICATION Switch between testing and production runs The ASW program package uses several routines from the LAPACK and BLAS libraries The source codes of these routines are included in the distribution and will be compiled and linked into the executables in case the entry LO CALLIB is left empty This option makes the ASW package completely self contained No additional libraries are necessary to run the programs Yet on most machines vendor specific installations of these libraries exist which are able to make use of machine specifications and thus in many cases are very fast Hence whenever a precompiled LAPACK or BLAS routine exists it s use is highly recommended In this case you should specify LOCALLIB USE Recent developments in the field of mathematical libraries have led to the Automatically Tuned Linear Algebra Subroutine ATLAS library which is available also for PC s running under Linux could be easily installed and outperforms even some vendor supplied libraries For the last item please use APPLICATION PROD Finally the installation directory where the executables and the LXTEXenvelope files will be copied must be given 2 Edit the files stuni f jbout f and timex f Select the settings valid for your machine by un commenting the correspond ing lines in the source code Yet due to the increased portability of Fortran95 this step can be skipped on most machines 3 Edit the file mnbeg f This f
126. mnbnd x which scans the k space path defined by tokens ENDPT and calculated eigenvalues the E k The result is written to file BNDE In addition if ORBWGT T has been specified eigenvectors i e wave functions are calculated for latter plotting of orbital weighted band structures as shown in Figs 2 3 to 2 6 and 2 14 The result is written to file BNDV Note that this file might be very large up to some hundreds of MByte In case you want to calculate orbital weighted band structures check the output file outbnd and search for the line beginning with File BNDV will need approx which gives a good estimate of the disk space needed 3 1 11 mmnall x Most of the aforementioned calculations can be made automatic by employing the shellscript mnall x which calls the program mnscf run successively for an increasing number of k points ranging from NKABC 6 to NKABC 30 After this it includes 0 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE the calculations already covered by the shellscripts mnbnd x and mndos x For com pounds with larger unit cells or for semiconductors and insulators it is recommended to copy the shellscript mnall x to the actual directory and delete the lines BINDIR upctr NKABC 16 NKABC 20 amp amp BINDIR mnscf run gt outlst20 amp amp BINDIR upctr NKABC 20 NKABC 30 amp amp BINDIR mnscf run gt outlst30 amp amp In this case the self consistent calculations will stop after the iterations fo
127. much faster as the complicated root tracing done before Finally as it stands the ASW package allows for non relativistic as well as scalar relativistic calculations and it can handle both spin restricted and spin polarized calculations the latter including a special branch for antiferromagnetic order Much work has been put into the code for accelerating the iterations towards self consistency Last not least due to the implementeation of the sphere geometry optimization 4 CHAPTER 1 INTRODUCTION SGO algorithm the ASW programs allow for considering closed packed systems as well as rather open crystal structures The SGO algorithm performs an automatic sphere packing including the generation of empty sphere positions and determination of optimal atomic sphere radii for use with the ASA Over the years more and more physical and chemical properties have become available by the ASW program package Among them are the following e Electronic Properties electronic dispersions E k band structure electronic wave functions H k projected band structure total partial site state projected densities of states DOS Fermi surface charge densities near future electric field gradients near future charge densities at the nuclei isomer shifts e Cohesive and Elastic Properties cohesive energy bulk modulus elastic constants near future phonon frequenc
128. n s Start of Iteration 7 3600 irreducible k points generated from 27000 30 30 30 Fermi energy MTZ 0 730387 Ryd D0S at Fermi energy 92 466301 1 Ryd Magnetic moment of UP atoms 1 711041 Magnetic moment of unit cell 0 000000 Mean square residual 0 270493D 12 Madelung energy 3 744479 Zeeman energy 0 000000 total 3pV 0 315314 virial energy 4794 054609 variational energy 4794 054649 qdiff 0 00000000 0 00000001 ediff 0 00000000 0 00000001 ASW 1 9 program MNSCF ended on majestix at Wed 13 Mar 2002 09 43 39 According to this output a magnetic solution with a magnetic moment of 1 74 per sublattice has indeed been found However while being stable as compared to the spin degenerate case its total energy is by 11 mRyd per formula higher as that of the ferromagnetic solution electronic structure is displayed in Fig 2 26 and the corresponding partial DOS given in Fig 2 27 Note the degeneracy of the spin up and spin down bands along most of the symmetry lines which is typical for an antiferromagnet splittings along the lines and A Z are indicative of the reduced symmetry of the antiferromagnetic structure which calls for a larger irreducible wedge of the first Brillouin zone Finally the partial Cr 3d to DOS are shown in Fig 2 28 where again the rotated reference frame was used In contrast to the ferromagnetic case energetical down shift of the spin up states is much less As
129. nimal set of symmetry operation the socalled generators of the space group By building all products of these generators the whole space group can be obtained This information can be used in two different ways First for GENPOS F the program performs a symmetry check using the information about the lattice and the atomic sites As a result all allowed symmetry operations are displayed In addition they are compared to the generators given in the CTRL file This cross check could be likewise used to force the program not to use the full crystal symmetry but only a subgroup of the space group E g if one specifies SYMOPS E then only the identity operation will be used in the k point loop hence the integration extends over the whole Brillouin zone rather than its irreducible wedge Second if GENPOS T is specified the program proceeds in a different way In this case the symmetry check of the atomic sites is omitted Instead the program generates all atomic sites by applying the symmetry operations which arise from the generators to all atoms in the CTRL file For this reason we would not have to specifiy all atomic sites but only one iron and one sulfur atom This is illustrated by the following listing 2 2 A MORE COMPLICATED STRUCTURE FES 31 HEADER FeS2 sc data by E D Stevens M L DeLucia and P Coppens Inorg Chem 19 813 1980 VERSION ASW 2 0 IO HELP F SHOW T VERBOS 30 CLEAN T OPTIONS REL T OVLCHK T STRUC ALAT 10 23476 SL
130. ntains a list of all atoms located within the space defined by tokens ORIGIN RPLOTI 2 2 A MORE COMPLICATED STRUCTURE FES 33 RPLOT2 and RPLOT3 These can be used for plotting the crystal structure To be specific type plstr x and enter the following dialog ASW 2 0 program PLSTR started on majestix at Mon 11 Mar 2002 12 38 05 Copyright C 1992 2002 Volker Eyert Please see file COPYRIGHT for details All input will be echoed to file PLIS Enter terminal type 1 X Windows default 2 PC Screen vt220 emulation 3 suppress terminal output Enter output device default 1 1 Color postscript 2 Postscript 3 GIF Enter title Use unit cell f default or Wigner Seitz cell t The following colours have been assigned to the classes FE red gt 9 green gt Select classes to be assigned a new colour enter blank or when you re done By default the bonds will be coloured orange 3 Enter blank or to accept or select from the following colours red r green g blue b 1 yellow y magenta n cyan c orange o blueviolet bv cyanogreen cg yellowgreen yg purple p cyanoblue cb violet v pale red pr pale blue pb pale green pg pale yellow py pale violet pv pale cyan pc black bk gray1 dark g1 gray2 g2 gray3 g3 gray4 g4 gray5 g5 gray6 lght g6 white wh Muffin tin spheres M default ASA spheres A
131. ntries CTRL_K2CuF4scoaf CTRL_K2CuF4scod05 CTRL_K2CuF4scod05af CTRL_K2CuF4scod10 CTRL_K2CuF4scod10af CTRL_K2CuF4scod15 CTRL_K2CuF4scodi5af CTRL_K2CuF4scod17 CTRL_K2CuF4scod17af CTRL_K2CuF4scod20 CTRL_K2CuF4scod20af CTRL_K2CuF4scod25 CTRL_K2CuF4scod25af CTRL_K2CuF4scod30 CTRL_K2CuF4scod30af CTRL_K2NiF4bct CTRL_K2NiF4sco CTRL_K2NiF4scoaf CTRL_K2NiF4scod05 CTRL_K2NiF4scod05af CTRL_K2NiF4scod10 CTRL_K2NiF4scod10af CTRL_K2NiF4scod15 CTRL_K2NiF4scod15af CTRL_K2NiF4scod20 CTRL_K2NiF4scod20af CTRL_KA13 CTRL_KB6 CTRL_Kr 115 CTRL_SmSe CTRL_SmTe CTRL_Sn CTRL 53525256 CTRL Sn02 CTRL_SnS CTRL SnSb02 CTRL Sr CTRL_Sr2Ru04 CTRL_Sr2Ti04 CTRL Sr2V04 CTRL_Sr6NGa5 CTRL_SrB6 CTRL_SrCd2Sb2 CTRL_SrCu3Ru4012 CTRL SrFe03 SrFe03afd SrFe03afz SrFe03fe CTRL SrTi03 CTRL_TTF TCNQ CTRL_Ta CTRL Ta218e8 CTRL Ta28e8 CTRL_TaCrAl CTRL_TaFe2 CTRL_TaFeAl CTRL_TaNiAl CTRL_TaS2 1T 116 CTRL Bi2Cu04 CTRL Bi28r2CaCu08 CTRL C CTRL_C3N4beta CTRL_C60 CTRL_Ca CTRL_Ca2NiSn CTRL_Ca2Ru041t CTRL_Ca2Ru04mt CTRL_Ca2Ru04so CTRL_Ca4Mn4010 CTRL_Ca7LaB48 CTRL_CaA12 CTRL_CaB6 CTRL_CaCu3Mn4012 CTRL_CaCu3Ru4012 CTRL_CaGa204sm CTRL_CaGa204smo CTRL_CaGa204so CTRL_CaGa204soo CTRL Ca0 CTRL_CaOn CTRL CaTi03 Cd CTRL_CdS CTRL_CdTe CTRL_Cdia CTRL_Ce CTRL_Ce2NiSn CTRL_CeAg CTRL_CeA12 CTRL_CeA13 CTRL_CeCu2Si2 CTRL_CeI2 CTRL CeIrIn5 CTRL_CeNi2Ge2 CTRL_CePd3 CTRL_CeRu2Si2 CTRL_Co4N C
132. oint and on adding the CPU time needed for the previous atomic calculations prints out the CPU time estimate for one iteration 4 12 CATEGORY CONTROL 107 4 12 5 Token CNVG cast double With this token the desired accuracy of the calculation is fixed Once this value has achieved the self consistency cycle stops In particular CNVG is the accuracy for the root mean square difference of the intraatomic charge density resulting from the previous and the present iteration The default value is CNVG 1 0D 8 which is very accurate You might well switch to CNVG 1 0D 6 without loosing to much However note that going from 1076 to 107 usually requires only very few iterations and hence can be achieved at a very low cost 4 12 6 Token CNVGET cast double This token specifies the desired accuracy for the total energy Whenever the differ ence between the total energies of the previous and the present iteration is below this value and the condition set by CNVG is fulfilled the self consistency cycly is stopped The default is CNVGET 1 0D 8 Ryd which again is very accurate 4 12 7 Token NITATM cast integer Actually there exist two different self consistency cycles within the ASW main pro gram mnscf run The outer cycle also called the band iteration is the usual one which aims at making the whole electronic charge density the effective potential the Hamiltonian matrix etc self consistent In addition the intratomic calcu
133. oken PSHIFT 4 14 12 Token CARTQ 4 14 13 Token QSWAVE 4 15 Category SYMLIN 4 15 1 Token NPAN 4 15 2 Token NPTS 4 15 3 Token 4 15 4 Token CARTE 4 15 5 Token LABEL 4 15 6 Token ENDPT 4 16 Category PLOT 4 16 1 Token CARTV 4 16 2 Token ORIGIN 4 16 3 Token RPLOT1 4 16 4 Token RPLOT2 4 16 5 Token RPLOT3 4 16 6 Token NPDIV1 4 16 7 Token NPDIV2 4 16 8 Token NPDIV3 5 The ASW database A Brillouin zones Bibliography 108 108 108 108 108 108 109 109 109 109 109 110 110 110 110 110 110 110 110 111 111 111 111 111 111 112 112 112 112 112 112 112 112 112 113 113 115 121 125 vi CONTENTS Chapter 1 Introduction 1 1 Overview Since its invention in the late seventies the Augmented Spherical Wave ASW method has become one of the most widespread methods used for density functional based electronic structure calculations Its minimal basis set allows for a natural interpretation of materials properties and makes it one of the fastest all electron methods The present User Guide addresses to practioners who want to apply the ASW method to actual problems but are not yet interested in a detailed understanding of the underlying formalism The original version of the ASW method was developed in the seventies at the IBM research lab in Yorktown Heights by A R Williams J K bler and C D Gelatt 10 According to the aut
134. olds the charge density and potential for plotting along the line or within a plane defined by tokens ORIGIN RPLOTI and RPLOT2 respectively An example is shown in Fig 2 11 where we identify the potential well FeS2 sc Figure 2 11 Overlapping free atom potential of fcc FeSo of the sulfur pair in the middle of the plot While program mnfre run merely serves the purpose of plotting the aformentioned quantities the actual search for possible empty sphere positions is done by a different program Type mnpac run or mnpac x to invoke the socalled sphere geometry optimization SGO algorithm This program proceeds in two different steps First it scans the overlapping free atom potential along lines connecting the atoms and finds optimal muffin tin radii i e radii for non overlapping spheres These are taken as a guidline for the atomic sphere radii Second it starts a search through the unit cell and identifies that position where the largest possible empty sphere could be placed Having found such a empty sphere candidate the radii of all spheres including the physical spheres and all empty spheres found so far are blown up until an acceptable overlap is reached With the resulting atomic sphere radii the overall space filling is checked and if this is not yet complete the process is repeated by searching for addtional empty spheres until the ASA condition is obeyed The program mnpac run generates two new files File STRU co
135. omic units UNITS BOHR default or Angstroems UNITS ANGS 4 5 2 Token ALAT mandatory cast double This token contains the lattice constant in the units specified by token UNITS The default is ALAT 0 0 As a consequence if the lattice constant is not given a finite value the program aborts Actually the tokens ALAT and PLAT below are complementary in that each of them can be scaled by a factor if the number s coming with the respective other token are scaled by the inverse An equivalent statement holds for the tokens and CBYA also given below As a consequence you may regard the input given by ALAT as a length scale for the whole crystal used for the primitive translations 4 5 3 Token PLAT mandatory cast double length 9 Information about the Bravais lattice is covered by this token which contains the three primitive translations a 1 2 3 in units of the lattice constant as specified by token ALAT All nine components must be given in the order air aiy A z 827 A3z 4 5 4 Token SLAT cast character As an alternative to explicitly specifying the primitive translations by PLAT you may use the following six tokens which rely on default lattice vectors coded in the ASW package First of all token SLAT indicates a string for the Bravais lattice Possible values are SC simple cubic BCC body centered cubic FCC cubic ST simple tetrag
136. onal BCT body centered tetragonal SO simple orthorhombic SCO base centered orthorhombic BCO body centered orthorhombic FCO face centered orthorhombic SM simple monoclinic SCM base centered monoclinic 94 CHAPTER 4 THE MAIN INPUT FILE CTRL TRI trigonal HEX hexagonal Note that the primitive translations coming with these specifications correspond to the definitions of Bradley and Cracknell which in some instances deviate from the definitions commonly used For this reason you are strongly urged to check the primitive translations which are printed to output at the beginning of the programs execution 4 5 5 Token BBYA cast double For the other lattice constants coming with non cubic and non trigonal systems there exist two different ways of specification token BBYA fixes the ratio of the lattice constants ALAT and BLAT As for ALAT above the default is BBYA 0 0 4 5 6 Token BLAT cast double Alternatively the additional lattice constant can be specified by the token BLAT which gives the lattice constant B explicitly in the units specified by token UNITS Again the default is BLAT 0 0 4 5 7 Token cast double This token comprises the ratio of the lattice constants C A The default is CBYA 0 0 4 5 8 Token CLAT cast double Alternatively the token CLAT allows to specify the lattice constant C explicitly in the units specified by token UNITS Default is CLAT 0 0 4 5 9 Token G
137. one in a clean and systematic style The source was held fully self contained by including standard 1 2 CHAPTER 1 INTRODUCTION BLAS or LAPACK routines for the linear algebra problems Graphics is based to large parts on Gnuplot which is likewise public domain software The file handling and the organization of the program was much improved taking away many stan dard steps from the users responsibility The interface between the user and the program was completely reshaped and now allows for a very flexible input Further more a lot more properties can be calculated which fact facilitates analysis of the electronic properties a lot and make the program exceptional among many other methods Last not least the program package has turned out to be very stable and efficient The latest version currently available is ASW 1 9 to which this handbook applies This version was originally designed for Unix Linux machines and most of the commands mentioned below refer to this environment More information about the ASW method and the program package can be obtained from the ASW homepage http www physik uni augsburg de eyert aswhome shtml where most of the properties accessible by the programs are discussed and a full list of publications and theses related to the ASW method is given Since 1998 a WINDOWS version of the present ASW version including a very clever graphics interface and access to the worlds largest crystallographic database is
138. ory can be used to influence the iteration towards self consistency Ac tually there exist two different self consistency loops One which is called the band iteration affects the calculation of partial charges and logarithmic derivatives for each orbtial once the Brillouin zone sampling has been finished The other in traatomic self consistency loop is performed for each atom as part of the intraatomic calculations All this is explained in more detail in my recent overview over the ASW method 5 Both types of iterations are accelerated by using the extended Anderson mixing which superseeds both the elder versions of the Anderson mixing and the Broyden update 2 The extended Anderson mixing is controlled by two parameters namely the number of previous iterations to be mixed in and the mixing parameter B values proposed for all tokens in this categories have been thoroughly tested in a huge number of applications They hardly need a change However whenever convergence is rather slow you might reduces the 0 value used for the band iterations to BETAB 0 3 and switch of the automatic increase of by setting INCBB F 4 13 1 Token cast integer This token holds the number of previous band iterations to be used for the band mixing The default is NMIXB 5 4 13 2 Token BETAB cast double Here you can specify the mixing parameter to be used for the band mixing The default is BETA 0 5 4 13 3 Token INCBB cas
139. packing routine stops Default value is RADMIN 0 5 which hardly has to be changed 4 9 7 Token RADMA X cast double The token RADMA X fixes the maximum atomic sphere radius for an empty sphere This setting has two opposing consequences large radius for an empty sphere might be prohibitive since higher and higher partial waves angular momenta would be needed to properly describe the electronic wave function within such a large sphere To the contrary if the maximum radius is set to rather small value it might be difficult to fill space by spheres if large voids exist in the crystal structure The default value is RADMAX 5 0 which is quite high in order not to limit the sphere size For most crystal structures you will not need to change this value Yet in case you obtain large empty spheres you might try RADMAX 3 0 4 9 8 Token POTWIN cast double As it stands the SGO algorithm aims at an optimal modeling of the full crystal potential by slightly overlapping spherical potential wells As a starting point for the full potential the overlapping free atom potential is used in a way first proposed by Mattheiss This potential is a continous function in all space If the potential is scanned along paths between the atomic sites the muffin tin radii are related to the maxima of the potential along these paths If overlapping spheres are sought for their radii correspond to positions on these paths where the potential is by a certain
140. r NK ABC 16 have converged 3 1 12 mnscl run mnscl x Whenever it is necessary to perform a supercell calculation this utility program does the supercell setup In the CTRL file an additional category SUPCELL must be given which otherwise looks identical to category STRUC but holds the information about the lattice of the supercell In addition token EQUIV F can be used to existing atomic files to equivalent files of atoms located in different regions of the new supercell Token PSHIFT will introduce an overall shift of all atoms and finally token QSWAVE holds spin wave vector of a collinear antiferromagnetic structure imposed on the supercell 3 1 13 upctr This shellscript allows to update the CTRL file Just type e g upshl ALAT 6 83079 ALAT 6 89979 to shrink the lattice constant of Cu by 1 or upctr QUIT QUIT BND to enforce a program stop after the band part Actually the script upctr is contained in many other of the above listed shellscripts 3 1 14 susan This utility shellscript has been created to extract a SUmmary of Selected results from the ASW output and to Notify about the progress of the iterations The shellscript is listed here bin sh HEHE Shell script susan SUmmarizes Selected results of the ASW self consistency cycle and Notifies about the progess of the iterations Version ASW 1 9 11 01 2002 Volker Eyert Copyright C 1994 2002 Volker Eyert Please see file COPYRIGHT for details
141. r any part of it or to incorporate any part of it into a commercial product without prior written permission of the author KK KK K KK FK KK FK KK FK K FK FK K FK ok FK FK FK K FK FK FK FK FK FK FK FK K FK K 3K FK FK K FK FK ok FK K FK FK FK K FK FK FK FK FK FK Disclaimer The ASW software package is distributed in the hope that it will be useful but WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTIBILITY or FITNESS FOR A PARTICULAR PURPOSE FK FK ook ok FK FK FK K FKK FK FK ok FK ok FK K FK FK 3K FK FK K FK FK FK FK FK FK FK FK K FK FK FK FK FK FK 1 7 KNOWN BUGS 9 1 7 Known bugs So far the following bugs are known which have not yet been removed from the code 1 The packing program mnpac run was originally designed for the spin degenerate case only As a consequence it produces wrong results if NSPIN 2 is specified in the CTRL file Please make sure that NSPIN 1 in the CTRL file or that this token is missing at all 1 8 Acknowledgement In setting up the ASW package I have benefitted from discussions with quite many people Not trying to be complete I mention especially Ole Andersen J rgen K bler Alexander Mavromaras Michael Methfessel Peter Schmidt Michael Stephan J rgen Sticht and Erich Wimmer 10 CHAPTER 1 INTRODUCTION Chapter 2 Execution of the ASW programs Examples In the pr
142. r rotation symbol E for unity R8 1 1 0 RA 1 1 0 Enter orbital s to be included Note notation of the orbitals refers to the rotated reference frame Select from the classes blank or to complete the list CR 0 1 2 CR Class CR atom 1 at 0 000000 0 000000 0 000000 Select from the following orbitals 0 all 1 all p 2 alld 158 257 3 2 4 X xy 6 yz 7 3z 2 r 2 8 Xz 9 x 2 y 2 9 Class CR atom 2 at 0 500000 0 500000 0 329790 Select from the following orbitals 0 all 1 all p 2 alld 1 s 2 y 3 2 4 x 5 Xy 6 yz 7 3272 72 8 2 9 x 2 y 2 Select from the classes blank or to complete the list CR 0 1 2 The following orbitals have been selected Class CR atom 1 orbital x 2 y 2 Please wait a moment I m reading the bands Timing for 19 points out of 194 0 00000 sec Ebot 19 922898 eV Etop 92 602619 eV relative to EF Emin 20 000000 eV Emax 6 000000 eV relative to EF Enter new Emin Emax to change these defaults 1 2 Rescale orbital weights default 0 0750eV 2 0 3 Please wait a moment I m working on the weights Timing for 19 points out of 194 0 01000 sec Enter the horizontal and vertical extension in mm Default 100 0x 90 0 task 1 total cpu time 0 16000 sec ASW 1 9 program PLBND ended on majestix at Thu 14 Mar 2002 15 54 09 As in Sec 2 1 4 the orbital to be included has to be specified Here the input 9 sel
143. ragonal SO simple orthorhombic SCO base centered orthorhombic BCO body centered orthorhombic FCO face centered orthorhombic SM simple monoclinic SCM base centered monoclinic TRI trigonal HEX hexagonal Note however that the primitive translations coming with these specifications corre spond to the definitions of Bradley and Cracknell which in some instances deviate from the definitions commonly used For this reason you are strongly urged to check the primitive translations which are printed to output at the beginning of the programs execution 4 14 4 Token cast double This token comprises the ratio of the supercell lattice constants B A Default is BBYA 0 0 110 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 14 5 Token BLAT cast double Alternatively this token allows to specify the supercell lattice constant B explicitly in the units specified by token UNITS Default is BLAT 0 0 4 14 6 Token CBYA cast double This token comprises the ratio of the supercell lattice constants C A Default is CBYA 0 0 4 14 7 Token CLAT cast double Alternatively this token allows to specify the supercell lattice constant explicitly in the units specified by token UNITS Default is CLAT 0 0 4 14 8 Token GAMMA cast double Here you insert the angle to be used for the monoclinic lattices Default value is GAMMA 0 0 4 14 9 Token EQUIV cast logical This switch enforces that after construction of
144. rations starting with the Brillouin zone sampling In case START has not been specified the default START BND will be used Furthermore the program will look up the atomic files and check them if present Depending on the outcome of this check the program will then decide automatically where to start In addition if START has been specified this setting is compared to the content of the atomic files and the program might opt for a different starting point If for instance the atomic sphere radii have been changed in the CTRL file and hence are no longer in agreement with those given in the atomic files the program will automatically invoke a restart calculation The same happens when change from a non spinpolarized to a spinpolarized calculation has been detected Another case to be mentioned is the situation where START REN is specified and 106 CHAPTER 4 THE MAIN INPUT FILE CTRL converged atomic files exist In this case the program stops in order to prevent the converged atomic files from being overwritten 4 12 2 Token QUIT cast character Token START is complemented by token QUIT which allows to stop execution prior to the end of the calculation normally performed by the program To be spe cific at present the following entries could be used QUIT SYM Any of the main programs stops after having performed the sym metry analysis QUIT OVL Any of the main programs stops after having performed the sym metry analysis and
145. s are superposed in order to have the potential along lines connecting all atoms From this information the muffin tin radii of the physical atoms can be evaluated In a second step the muffin tin radii are blown up until the overlap limits specified by tokens OBYDMX and OBYRMX are reached If space filling as fixed by token FILLING can not yet be achieved a search for the largest possible empty sphere sets in Once this has been found again all spheres are blown up until the maximum space filling compati ble with the overlap limits is reached This process is repeated until full space filling has been achieved However see the description of all tokens in category PACK for more detailed information WARNING As it stands this program was designed for the spin degenerate case only So make sure that NSPIN 1 or this token is missing at all in the CTRL file 3 1 7 mnstr x This special variant of shellscript mnpac x likewise calls the packing program but stops after the determination of the muffin tin radii The result as contained in file STRU can be used for plotting the crystal structure with the plot program plstr run or plstr x 3 1 8 mnscf run mnscf x This is the most comprehensive of all programs After reading the CTRL file it per forms the self consistent calculations until full convergence or the maximum iteration count as specified by token NITBND has been reached In this course the program calculates partial charges and ma
146. sarily overlapping atomic spheres this would lead to too large overlap regions in the pyrite structure We recall that the ASA as introduced by Andersen was meant as an approximation to the full crystal potential which could be well modeled by slightly overlapping potential wells validity of this approach has been checked in a lot of cases However for open crystal structures the approximation becomes to crude and a trick has to be applied It consists of inserting socalled empty spheres into the crystal structures within which the electronic charge density and potential can vary and hence help modeling the total potential in a much improved way Again this has been checked with full potential calculations which include the full crystal potential rather than employing the shape approximation coming with the 32 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES ASA As a matter of fact surprisingly good agreement has found For the present case two additional programs come into play First type mn fre run or mnfre x This program will calculate the charge density and potential arising from the superposition of these quantities as calculated for free atoms lo cated at the respective crystallographic sites As has been argued by Mattheiss the resulting potential resembles the final full crystal potential very much and hence can be well used to locate the position of possible empty spheres The program gen erates a file FREE which h
147. st if the numbers for the two highest orbitals and their sum is below 0 1 electrons you might decrease the value set by LMXL by one This has been already done in the above listed CTRL file Note that each orbital included recall that there are 21 1 states for each l increases 38 CHAPTER 2 EXECUTION OF THE ASW PROGRAMS EXAMPLES the size of the secular matrix and thus leads to an increase of execution time and memory CPU time scales roughly with the cube of the number of orbitals In case you realize during the first iterations that the number of orbitals for a particular atom should be changed you have to stop execution and delete all atomic files those given by the entries ATOM in category CLASS In addition you must delete the file MIX which holds information about the progress of the iterations and is deleted automatically once self consistency has been reached After that adjust the angular momenta given by the tokens LMXL In case you have increased the LMXL values corresponding entries have to be added to tokens CONF and QVAL However these latter tokens could likewise be completely erased since the program creates them automatically Finally the calculation can be restarted by typing mnscf x or mnall x at the systems prompt For the latter the complete cycle of calculations will take several hours enough for a coffee break 2 2 3 Execution of the plot programs After the self consistent field calculations have converge
148. t atomic positions as cartesian CHOUT of cast logical Switch to change interpretation of atomic positions ATOM of cast character mandatory Class labels POS of cast double and length 3 mandatory Positions of basis atoms 8 CHAPTER 3 ORGANIZATION THE ASW PROGRAM PACKAGE token SPIN of cast character String characterizing the spin direction category SYMGRP token GENPOS of cast logical Switch to complete atomic basis by use of symmetry token SYMOPS of cast character and length 48 Strings for space group generators token CARTR of cast logical Switch to treat rotation axes as cartesian token CARTT of cast logical Switch to treat fractional translations as cartesian category PACK token FILLNG of cast double Filling factor for atomic sphere volumes token OBYDMX of cast double Maximum allowed overlap distance token OBYRMX of cast double Maximum allowed overlap radius token ESBONS of cast double Empty sphere bonus to be added to OBYDMX and OBYRMX token NCEMAX of cast integer Maximum number of allowed empty sphere classes token RADMIN of cast double Minimum muffin tin radius for empty spheres token RADMAX of cast double Maximum atomic sphere radius for empty spheres token POTWIN of cast double Potential window used for setup of radii window token RADACC of cast double Accuracy required for sphere radii token POSACC of cast double Accuracy required for empty sphere positions category ENVEL token N
149. t double Supercell lattice constant B in UNITS CBYA of cast double Ratio of the supercell lattice constants C A CLAT of cast double Supercell lattice constant C in UNITS GAMMA of cast double Angle used for the monoclinic supercell lattices EQUIV of cast logical Switch to keep subcells equivalent CARTS of cast logical Switch to treat position shift vector as cartesian PSHIFT of cast double and length 3 Shift vector for the supercell atomic positions CARTQ of cast logical Switch to treat spin wave vector as cartesian QSWAVE of cast double and length 3 Spin wave vector of collinear antiferromagnets y SYMLIN NPAN of cast integer Number of symmetry lines panels NPTS of cast integer Maximum total number of points ORBWGT of cast logical Switch to calculate orbital weights SPATH of cast logical Switch to use spherical pathways EPHOT of cast double Photon energy fixing the radius of the sphere CARTE of cast logical Switch to treat endpoints as cartesian LABEL of cast character Labels of endpoints ENDPT of cast double and length 3 Endpoints of symmetry lines RDKPT of cast logical Switch to read points from file y PLOT CARTV of cast logical Switch to treat plot vectors as cartesian ORIGIN of cast double and length 3 Origin of plot space RPLOT1 of cast double and length 3 Plot vector specifying plot space RPLOT2 of cast double and length 3 Plot vector specifying plot space
150. t logical With INCBB T this switch allows to increase the 0 value used for the band itera tions hence to speedup these iteration once the self consistency loop has stabilized 4 13 4 Token NMIXA cast integer This token holds the number of previous intraatomic iterations to be used for the atomic mixing The default is NMIXA 5 4 13 5 Token cast double Here you can specify the mixing parameter to be used for the intraatomic mixing The default is BETA A 0 5 4 14 CATEGORY SUPCELL 109 4 14 Category SUPCELL 4 14 1 Token ALAT cast double This token contains the supercell lattice constant in the units specified by token UNITS Default is ALAT 0 0 4 14 2 Token PLAT cast double length 9 Information about the Bravais lattice is covered by this token which contains the three supercell primitive translations a i 1 2 3 in units of the lattice constant All nine components must be given in the order air A z 4 14 3 Token SLAT cast character As an alternative to explicitly specifying the supercell primitive translations by PLAT you may use the following six tokens which rely on default lattice vectors coded in the ASW package First of all token SLAT indicates a string for the Bravais lattice Possible values are SC simple cubic body centered cubic FCC cubic ST simple tetragonal BCT body centered tet
151. t stands the ASW program package is fully self contained without the need to link any library Standard routines for e g matrix inversion and diagonalization are taken from the LAPACK library For plotting the calculated data the programs pro vide interfaces to GNUPLOT RASMOL and XMakeMol which are public domain software a consequence commercial libraries are not needed at all Finally the program is fully portable to and has been tested on a large variety of platform including e IBM RS6000 xlf xIf90 e HP 9000 HP UX f90 e CRAY Y MP YEL J90 T90 UNICOS 90 e SNI 5400 UXP M frt e SNI VPP500 UXP M frtpx e Sun SPARC Solaris f90 e Convex ConvexOS fc f90 e Compaq Alpha True64 UNIX f90 e PC AMD Intel Linux VAST f95 Lahey Fujitsu Fortran f95 PGI f90 Ab softPro Fortran NAG f95 e PC AMD Intel Windows95 98 NT Compaq Visual Fortran Lahey Fortran 95 e all platforms GNU g95 For this reason installing the package poses no problems and can be done within a few minutes 6 CHAPTER 1 INTRODUCTION 1 4 Installation Since the ASW package has been written with portability in mind installation on various platforms is straightforward In particular only few steps are needed 1 Edit the Makefile In the first part of the Makefile several items must be specified COMPILER Machine and or compiler ARCH Machine architecture for IBM only LOCALLIB Use of local BLAS library reco
152. tate orbitals net atomic charge Madelung potential muffin tin zero and total energy contributions MOMS Charges and energies as arising from the momentum analysis of the partial densities of states LDER Logarithmic derivatives and P functions for all partial waves ESJH Hankel and Bessel energies and integrals for use in the intraatomic integrals entering the secular matrix VMTA Spherical symmetric intraatomic single particle potential RHOV Spherical symmetric intraatomic valence electron charge density CORE Core state energies and spherical symmetric intraatomic core electron charge density An example atomic file looks like GEN CU written by ASW 1 9 Z 29 LMXL 2 LMXI 3 CONF 4 4 34 NSPIN 1 REL T RMAX 2 669448 NR 541 AR 0 200000000 01 BR 0 544565163250D 04 NCORE 5 LCORE 000 11 QCORE 18 NKAP 1 EKAP 0 015000 QATM 0 899994592740D 10 VMAD 0 000000000000D 00 VMTZ 0 723947535848D 00 VRMAX 0 210033940992D 02 3 4 DATA FILES 83 EVBM 0 113021354253D 01 0 470014259154D 00 EFERM 0 641841988344D 00 EHRTR 1438 20951104 EXCSM 130 04186989 VXCSM 172 17863463 SUMTC 3114 31998034 SUMEC 1905 37188135 SUMTV 186 76405917 SUMEV 3 44125736 3pV 0 17025757 3pV T 3304 88587275 ETVAR 3304 88588502 MOMS CU NL QMOM1 QMOM2 EMOM1 EMOM2 40 0 4583953828D 00 0 2430151755D 00 0 6119260083D 00 0 27418187020 00 41 0 3397801707D 00 0 3913002460D 00 0 5024522894D 00 0 2199454608D 00 3 2 0 39603
153. ted from the converged moments or the logarithmic derivatives they can be removed in the atomic files once a calculation has been completed token CLEAN which by default is CLEAN T makes the program delete the charge density and potential information i e the categories VM TA RHOV and CORE from the atomic file and thus allows for much reduced storage needs Yet see token CORDRD below for exceptions 4 3 6 Token WRITE cast character Here you can specify the name of an updated backup version of the CTRL file which will be written just before completion Default is WRITE CBAK 4 3 7 Token EXTENS cast character Using this token you may specify a standard extension appended to all file names created by the program as e g dat This is meant to conform with WINDOWS or VAX file name conventions The default is empty hence all file names come without an extension 4 4 Category OPTIONS The following tokens can be used to specify details of the calculations 4 4 1 Token REL cast logical This token allows to switch between non relativistic and scalar relativistic mode The default is REL T scalar relativistic 4 4 2 Token LSCPL cast logical In future versions this token will enable for including the LS coupling which how ever is not yet implemented 4 4 3 Token NSPIN cast integer Here you can specify the number of spin channels Default is NSPIN 1 4 4 CATEGORY OPTIONS 91
154. teger In addition for each atom a maximum angular momentum for the intermediate waves is needed These waves are used for expanding the Hankel envelope functions at neighbouring sites in Bessel envelope functions As a default the input for the lower wave maximum angular momentum plus one is used Especially for small empty spheres which carry very small amount of charge already in their lower partial wave it is useful to set the maximum value for the intermediate waves to that for the lower waves To the contrary only rare situations exist where lint should be low 2 4 6 8 Token CONF cast integer length 4 While the previous two tokens specify the maximum number of partial waves per atoms the principal quantum numbers for all these orbitals must be given here Again the default values are taken from a small database in accordance with the above input for the atomic number 4 6 9 Token COORB cast integer With this token you can select the orbitals which you want ot be included in the calculation as well as presentation of the crystal orbital overlap population COOP the crystal orbital Hamiltonian population COHP or the covalence energy Ec The input consists just of the angular momenta of the desired orbital i e for in cluding p and states you write COORB 1 2 As a default no orbitals will be included 4 6 10 Token QVAL cast double length 4 This token holds the valence charges for each atom which wi
155. tegrations For examples with NKABC 6 6 6 the Brillouin zone is divided into 216 microcells A special notation has been invented for this token which makes life much easier Whenever one of the three numbers is set to 0 in the CTRL file it is interpreted by the programs as being identical to the preceding number be specific the following interpretations can be used NKABC 6 00 6 6 6 6 80 6 8 8 6 08 6 6 8 This feature enables fast switching to a finer grid after a calculation with a coarse grid has converged The default setting for this token is NKABC 8 0 0 However most cases it is best to start from NKABC 6 0 0 After convergence one should switch to NKABC 8 0 0 then 12 16 20 and 30 This way the dependence of the results on the fineness of the k grid could be checked For metals going up to NKABC 30 0 0 suffices in almost all cases except for the nearly free electron metals like Al and Na In contrast for semiconductors and insulators much lower values as e g 16 0 0 are enough same holds for rather large unit cells comprising e g 30 or more atoms Since these unit cells have smaller Brillouin zones going up to NKABC 16 0 0 will also suffice Of course these numbers are only rough estimates the particular choice being more or less matter of the desired accuracy 4 11 2 Token BZINT cast character The token BZINT allows to choose the
156. the structure and content of the CTRL file which is the main input file for the ASW package and hence the only interface between the user and the main programs Besides information on the crystal structure and the atoms making the crystal it contains also more technical parameters controlling the execution The CTRL file is fully free format i e users do not have to obey any format specification Yet the file must not contain any TABs It is important to notice that the CTRL file is a exclusively used as an input file to the programs None of the programs writes to this file at all Only some shell scripts like are allowed to manipulate the CTRL file see below As a consequence the CTRL file will never be destroyed even if you interrupt the program during execution or if your computer crashes Whenever the program creates new data as e g empty sphere positions atomic radii or a supercell it generates a new CTRL file called CNEW In addition most of the programs write an updated copy of CTRL to the file specified by the token WRITE which by default is CBAK The CTRL file is grouped into categories each starting in the first column of the file Each category contains tokens specifying a portion of the input e g in order to specify the lattice constant you just write ALAT 6 76 somewhere in the category STRUC A complete list of all categories and tokens is supplied in the file HELP which is printed in Sec 3 4 It is incl
157. the supercell atoms located at the equivalent positions in different subcells still belong to the same class even if they are not related by a symmetry operation of the supercell The default is EQUIV T 4 14 10 Token CARTS cast logical This switch specifies whether the following entries for the shift vector are interpreted as Cartesian coordinates CARTS T or as relative components in terms of the primitive translations CARTS F The default value is CARTS T 4 14 11 Token PSHIFT cast double length 3 This token holds a shift vector which is added to all atomic positions after a supercell has been constructed Note however that in order to avoid confusion this token is interpreted only by routine mnscl The default is PSHIFT 0 0 0 0 0 0 4 14 12 Token CARTQ cast logical This switch specifies whether the following entries for the spin wave vector are in terpreted as Cartesian coordinates CARTQ T or as relative components in terms of the primitive translations CARTQ F The default value is CARTQ T 4 15 CATEGORY SYMLIN 111 4 14 13 Token QSWAVE cast double length 3 With this token you may specify a spin wave vector for a collinear antiferromag netic structure to be imprinted on the supercell The simplest case is that of doubling the unit cell and treating the two subcells as the spin up and spin down sublattice The spin wave vector must be given in units of 27 divided by the supercell lattice constant a its
158. tion of all partial DOS during iteration towards self consistency For this reason the default is SAVDOS F Once full self consistency is achieved you can choose SAV DOS T and calculate the partial densities of states for plotting in one additional calculation It is advantageous to switch from BZINT SMS to BZINT HPS in this case too 4 11 10 Token SAVCOOP cast logical The meaning of this token is equivalent to that of the previous token During the iterations SAVCOOP F should be used in order to suppress calculation of the crystal orbital overlap populations COOP the crystal orbital Hamiltonian population COHP or the covalence energy at all The input consists just of the angular momenta of Only in the additional run after self consistency has been reached SAVCOOP T might be used Note that the latter choice is only effective if the orbitals to be included have been specified by tokens COORB in category CLASS 4 11 11 Token cast character The token CTYPE allows to choose the scheme used to describe chemical bonding At present it can be either CTYPE COOP for the crystal orbital overlap popu lation introduced by Hoffmann for the crystal orbital Hamilton population as proposed by Dronskowski and Bl chl and CTYPE ECOV for the covalence energy put forward by F hnle and coworkers 4 11 12 Token MSPLIT cast logical This token allows to calculated m resolved COOP s However this fea
159. ture has not been fully tested and in addition requires additional CPU time and memory For these reasons the default is MSPLIT F 4 11 13 Token TEMPFD cast double With this token you can specify the temperature in Kelvin entering the Fermi Dirac distribution function which will be used for folding with the calculated density of states This allows to evaluate the position of the chemical potential from the condition that at the given temperature the numbers of excited holes and electrons must be identical In a second step these numbers are resolved in contributions from atoms and angular momenta i e the partial numbers of excited holes and electrons are calculated This helps to quickly identify the relevant optical transitions The default is TEMPFD 300 4 12 CATEGORY CONTROL 105 4 12 Category CONTROL 4 12 1 Token START cast character The tokens START and QUIT can be used to control the sequence of all cal culations performed during execution esepcially of program mnscf run In general ASW calculations towards self consistency are subdivided into two parts In one part starting from integrals of the partial waves the program sets up as well as diagonalizes the secular matrix for every k point and supplies the first four mo ments of the partial densities of states This part is called the band calculation In the other part the moments of the partial densities of states are used to calculate intraatomic wave fun
160. u should not go beyond OBYDMX 0 2 4 9 3 Token OBYRMX cast double Maximum allowed overlap for any pair of spheres scaled to the radii of the respective spheres Default value is OBYRMX 0 4 but OBYRMX 0 5 is still acceptable This token is important for systems containing large differences in sphere radii where hence small spheres might be swallowed by large spheres if e g touching spheres are blown up to space filling 100 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 9 4 Token ESBONS cast double Since the empty spheres are included in order to mimic the full crystal potential in large voids between the physcial spheres the potential within these spheres is rather flat For that reason empty spheres can have a larger overlap with the neighbouring spheres ESBONS specifies this extra bonus to be to OBYDMX and OBYRMX Default is ESBONS 0 05 and the actual value should not exceed ESBONS 0 1 4 9 5 Token cast integer This token fixes the maximum number of empty sphere classes sought for by the program If space filling can not be achieved with less empty spheres the program issues a warning saying that the result of the sphere packing might depend on this parameter The default value is 256 4 9 6 Token RADMIN cast double This token gives the minimum muffin tin radius for an empty sphere Once the SGO algorithm subsequently identifies two possible empty spheres candidates with muffin tin radii smaller than RADMIN the
161. uded as a separate file in the ASW package but could be generated running any of the main programs with HELP T in category IO of the CTRL file At present the ASW program package interprets 118 tokens grouped in 16 differ ent categories However fortunetely only entries in three different categories must be specified by the user For all other tokens exist meaningful and well tested de fault values Information required from the user is related to the crystal s Bravais lattice the type of atoms included their atomic numbers and the positions of these species within the unit cell of the crystal These three types of information go into the categories STRUC CLASS and SITE respectively which therefore are marked mandatory in the list below Once you start the program it automatically creates the atomic files which have just the names specified by token in category CLASS There is only one file for each atom program also creates one file for the mixing file MIX and deletes it after self consistency has been reached In addition files DOS and 8T 88 CHAPTER 4 THE MAIN INPUT FILE CTRL COOP both unformatted are created and written to in case you set SAVDOS T and SAVCOOP T respectively in category BZSMP A short version of the following explicit description is given in the HELP file which comes with the distribution but can be easily created by specifying HELP T in category OPTIONS and running any of the ASW main
162. ur This is different for the bands highlighted in Figs 2 21 and 2 22 which display dispersions of a similar size along all lines 2 3 3 Spin polarized ferromagnetic calculations Before adapting the CTRL file for the spin polarized calculations you should copy it to another directory in order to preserve the results of the non magnetic calcu lations In order to perform spin polarized calculations two new tokens have to be added to the new CTRL file In category OPTIONS the entry NSPIN 2 must be inserted which tells the program to perform a spin polarized calculation Further more each orbital has to be given a starting value for the polarization Otherwise the calculation would again converge to the spin degenerate solution Breaking the spin symmetry is achieved by adding the token MVAL for each atomic class in category CLASS followed by the polarization for each orbital For ferromagnetic CrO the new categroy CLASS looks like the following CLASS ATOM CR Z 24 R RA 2 14485 LMXL 2 CONF 4 4 3 4 QVAL 1 0 0 0 5 0 0 0 MVAL 0 0 0 0 2 0 0 0 Z 8 R RA 1 83785 LMXL 1 CONF 2 2 3 QVAL 2 0 4 0 0 0 MVAL 0 0 0 0 0 0 1 Z 0 R RA 1 65282 LMXL 1 CONF 1 2 3 QVAL 0 0 0 0 0 0 MVAL 0 0 0 0 0 0 ATOM E2 Z 0 R RA 1 76299 LMXL 1 CONF 1 2 3 QVAL 0 0 0 0 0 0 MVAL 0 0 0 0 0 0 Z 0 R RA 0 77096 LMXL 0 CONF 1 2 QVAL 0 0 0 0 MVAL 0 0 0 0 Once these changes have been made you could type mnall x as in the sp
163. whole energy range They grow out of the aforementioned parabolic like band which leads in particular to the square root behaviour of the 4s partial DOS at low energies At higher energies the 3d states set in which are limited to the energy interval between 5 5 and 1 5 eV but give large contributions As for the band structure an echo file has been created which is called PLID Rename this file to e g PLIDf and type pldos x PLIDf in order to reproduce the plot Of course this plot routine could be also called without using the shell script in which case we would have to type pldos run PLIDf at the systems prompt Note the Unix Linux here which is already included in the shellscript 2 1 4 Advanced features So far we were able to decompose the total DOS into partial densities of states and were thus able to identify orbital contributions in certain energy intervals However 22 CHAPTER 2 EXECUTION THE ASW PROGRAMS EXAMPLES corresponding analysis at a k point level would be welcome Such a tools exists in the ASW program package In order to use it we enter the CTRL file and change in category SYMLIN the token NPTS 400 to NPTS 200 and ORBWGT F to ORBWGT T It is suggested to first copy the files CTRL and CU to a separate directory and do the changes of the CTRL file there After having changed the CTRL file as described type mnbnd x As before this will produce a file BNDE In addition a file named BNDV is generated wh
164. you can specify a verbosity level for printing the output The following ver bosity levels are at present in use verbosity gt 0 nearly nothing is printed gt 10 very terse gt 20 terse 230 normal gt 40 verbose gt 50 very verbose gt 60 higher verbosity gt 80 highest verbosity gt 100 low level debugging 110 intermediate level debugging gt 120 high level debugging The default is VERBOS 30 In normal operation you should not go beyond VER BOS 50 In particular for VERBOS 80 the Hamiltonian matrix and related matrices are written to the output file which hence will become very large 4 3 4 Token IACTIV cast logical In future versions this token will allow to switch to an interactive mode 90 CHAPTER 4 THE MAIN INPUT FILE CTRL 4 3 5 Token CLEAN cast logical Like the CTRL file the atomic files are organized in a collection of categories named GEN MOMS LDER ESJH VMTA RHOV and CORE The first four of these comprise respectively general information about the atom at hand the moments of the partial densities of states the partial logarithmic derivatives and the partial Hankel and Bessel energies and integrals Finally the last three and by far most extensive groups contain the effective single particle potential as well as the self consistent valence and core charge densities Since within the standard ASW method the latter three entities can be easily genera

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