[Wien] re : Supercells - what is the right procedure to create an acceptable one?

[Torsten Andersen]

In your case, I would recommend decreasing RMT to, say, 1.40. The choice 
of maximum-sized RMT's is not the best one if one uses mini (as you can 
see below).

Best regards,
Torsten Andersen.

George Amolo wrote:
> Dear Wien2k users,
> 
> I am a fairly new user of the Wien2k code trying out some calculations of
> dopant impurities in a diamond lattice supercell. The users forum has been
> of immense help to me. I have followed with interest suggestions of Steven
> Homolya (21st - 23rd October 2004) on how to fix hand-made struct files
> and hence modify them to supercells. The last email, 23rd October, has a
> caution from Jorrisen Kevin about the CXZ-bug if one accepts all the
> output from sgroup. Would someone out there kindly outline in simple terms
> what should be done.
> 
> I have started out with (despite Stefan's caution to Yaron and Angelica of
> 18th Jul 2003 not to give a spacegroup but rather start from a
> P-structfile. This is because that route had even more problems)
> 
> diamond
> F   LATTICE,NONEQUIV. ATOMS  1227_Fd-3m
> MODE OF CALC=RELA unit=bohr
>   6.740660  6.740660  6.740660 90.000000 90.000000 90.000000
> ATOM   1: X=0.12500000 Y=0.12500000 Z=0.12500000
>           MULT= 2          ISPLIT= 2
>        1: X=0.87500000 Y=0.87500000 Z=0.87500000
> C C1       NPT=  781  R0=0.00010000 RMT=    1.4500   Z:  6.0
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                      0.0000000 1.0000000 0.0000000
>                      0.0000000 0.0000000 1.0000000
> 
> and went ahead to use the 'supercell' command online. Several warnings
> appeared. I went ahead and accepted the suggested changes by updating them
> to the case.struct file and then through the process of intialization of the
> struct file which is now essentially that of a supercell. Note that a
> nitrogen atoms was inserted into the supercell. The struct file before
> running 'mini' is
> 
> Title
> R                            4 166 R-3m
>              RELA
>   9.532733  9.532733 23.350331 90.000000 90.000000120.000000
> ATOM  -1: X=0.31278464 Y=0.31278464 Z=0.81217227
>           MULT= 6          ISPLIT= 8
>       -1: X=0.81217227 Y=0.31278464 Z=0.31278464
>       -1: X=0.31278464 Y=0.81217227 Z=0.31278464
>       -1: X=0.68721536 Y=0.68721536 Z=0.18782773
>       -1: X=0.68721536 Y=0.18782773 Z=0.68721536
>       -1: X=0.18782773 Y=0.68721536 Z=0.68721536
> C 1        NPT=  781  R0=.000100000 RMT=   1.45000   Z:   6.00000
> LOCAL ROT MATRIX:    0.0000000 1.0000000 0.0000000
>                      0.0000000 0.0000000 1.0000000
>                      1.0000000 0.0000000 0.0000000
> ATOM  -2: X=0.81302209 Y=0.81302209 Z=0.30880538
>           MULT= 6          ISPLIT= 8
>       -2: X=0.30880538 Y=0.81302209 Z=0.81302209
>       -2: X=0.81302209 Y=0.30880538 Z=0.81302209
>       -2: X=0.18697791 Y=0.18697791 Z=0.69119462
>       -2: X=0.18697791 Y=0.69119462 Z=0.18697791
>       -2: X=0.69119462 Y=0.18697791 Z=0.18697791
> C 2        NPT=  781  R0=.000100000 RMT=   1.45000   Z:   6.00000
> LOCAL ROT MATRIX:    0.0000000 1.0000000 0.0000000
>                      0.0000000 0.0000000 1.0000000
>                      1.0000000 0.0000000 0.0000000
> ATOM  -3: X=0.31301112 Y=0.31301112 Z=0.31301112
>           MULT= 2          ISPLIT= 4
>       -3: X=0.68698888 Y=0.68698888 Z=0.68698888
> N 1        NPT=  781  R0=.000100000 RMT=   1.45000   Z:   7.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                      0.0000000 1.0000000 0.0000000
>                      0.0000000 0.0000000 1.0000000
> ATOM  -4: X=0.81511300 Y=0.81511300 Z=0.81511300
>           MULT= 2          ISPLIT= 4
>       -4: X=0.18488700 Y=0.18488700 Z=0.18488700
> C 3        NPT=  781  R0=.000100000 RMT=   1.45000   Z:   6.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                      0.0000000 1.0000000 0.0000000
>                      0.0000000 0.0000000 1.0000000
>   12      NUMBER OF SYMMETRY OPERATIONS
>  1 0 00.00000000
>  0 1 00.00000000
>  0 0 10.00000000
>    1
>  0 0 10.00000000
>  1 0 00.00000000
>  0 1 00.00000000
>    2
>  0 1 00.00000000
>  0 0 10.00000000
>  1 0 00.00000000
>    3
>  0-1 00.00000000
> -1 0 00.00000000
>  0 0-10.00000000
>    4
> -1 0 00.00000000
>  0 0-10.00000000
>  0-1 00.00000000
>    5
>  0 0-10.00000000
>  0-1 00.00000000
> -1 0 00.00000000
>    6
> -1 0 00.00000000
>  0-1 00.00000000
>  0 0-10.00000000
>    7
>  0 0-10.00000000
> -1 0 00.00000000
>  0-1 00.00000000
>    8
>  0-1 00.00000000
>  0 0-10.00000000
> -1 0 00.00000000
>    9
>  0 1 00.00000000
>  1 0 00.00000000
>  0 0 10.00000000
>   10
>  1 0 00.00000000
>  0 0 10.00000000
>  0 1 00.00000000
>   11
>  0 0 10.00000000
>  0 1 00.00000000
>  1 0 00.00000000
>   12
> 
> I invoked  min_lapw -j 'run_lapw -I -fc 1.0 -i 50' for a trial minimization
> and run the following 'mini' error after more than an hour
> 
>  'NN' - overlapping spheres
>  'NN' - RMT( 1)=1.45000 AND RMT( 2)=1.45000
>  'NN' - SUMS TO 2.90000 GT NNN-DIST= 2.89817
> 
> Please advice me on this rather long story. Thank you.
> 
> george Amolo
> 
> 
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> 

-- 
Dr. Torsten Andersen        TA-web: http://deep.at/myspace/
AG Hübner, Department of Physics, Kaiserslautern University
http://cmt.physik.uni-kl.de    http://www.physik.uni-kl.de/