[Wien] Si under strain

Fecher, Gerhard fecher at uni-mainz.de
Thu Sep 10 15:24:48 CEST 2015 

Then
https://www.webelements.com/silicon/crystal_structure.html
is wrong !

Before you start calculations you should know the crystal structure very well and you should know about symmetry and space groups.

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden
________________________________________
Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Muhammad Sajjad [sajjadpu at gmail.com]
Gesendet: Donnerstag, 10. September 2015 14:51
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] Si under strain

It is 216_F-43m

On Thu, Sep 10, 2015 at 1:51 PM, Muhammad Sajjad <sajjadpu at gmail.com<mailto:sajjadpu at gmail.com>> wrote:
Here is the structure file script.


Title
F   LATTICE,NONEQUIV.ATOMS:  2 216_F-43m
MODE OF CALC=RELA unit=ang
 10.263031 10.263031 10.263031 90.000000 90.000000 90.000000
ATOM   1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 2
Si         NPT=  781  R0=0.00010000 RMT= 2.21        Z: 14.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM   2: X=0.25000000 Y=0.25000000 Z=0.25000000
          MULT= 1          ISPLIT= 2
Si         NPT=  781  R0=0.00010000 RMT= 2.21        Z: 14.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
  24      NUMBER OF SYMMETRY OPERATIONS
 1 0 0 0.00000000
 0-1 0 0.00000000
 0 0-1 0.00000000
       1
 1 0 0 0.00000000
 0 0-1 0.00000000
 0-1 0 0.00000000
       2
 0 1 0 0.00000000
-1 0 0 0.00000000
 0 0-1 0.00000000
       3
 0 0 1 0.00000000
-1 0 0 0.00000000
 0-1 0 0.00000000
       4
 0 1 0 0.00000000
 0 0-1 0.00000000
-1 0 0 0.00000000
       5
 0 0 1 0.00000000
 0-1 0 0.00000000
-1 0 0 0.00000000
       6
 0-1 0 0.00000000
 1 0 0 0.00000000
 0 0-1 0.00000000
       7
 0 0-1 0.00000000
 1 0 0 0.00000000
 0-1 0 0.00000000
       8
-1 0 0 0.00000000
 0 1 0 0.00000000
 0 0-1 0.00000000
       9
-1 0 0 0.00000000
 0 0 1 0.00000000
 0-1 0 0.00000000
      10
 0-1 0 0.00000000
 0 0-1 0.00000000
 1 0 0 0.00000000
      11
 0 0-1 0.00000000
 0-1 0 0.00000000
 1 0 0 0.00000000
      12
 0 0 1 0.00000000
 0 1 0 0.00000000
 1 0 0 0.00000000
      13
 0 1 0 0.00000000
 0 0 1 0.00000000
 1 0 0 0.00000000
      14
-1 0 0 0.00000000
 0 0-1 0.00000000
 0 1 0 0.00000000
      15
-1 0 0 0.00000000
 0-1 0 0.00000000
 0 0 1 0.00000000
      16
 0 0 1 0.00000000
 1 0 0 0.00000000
 0 1 0 0.00000000
      17
 0 1 0 0.00000000
 1 0 0 0.00000000
 0 0 1 0.00000000
      18
 0 0-1 0.00000000
 0 1 0 0.00000000
-1 0 0 0.00000000
      19
 0-1 0 0.00000000
 0 0 1 0.00000000
-1 0 0 0.00000000
      20
 0 0-1 0.00000000
-1 0 0 0.00000000
 0 1 0 0.00000000
      21
 0-1 0 0.00000000
-1 0 0 0.00000000
 0 0 1 0.00000000
      22
 1 0 0 0.00000000
 0 0 1 0.00000000
 0 1 0 0.00000000
      23
 1 0 0 0.00000000
 0 1 0 0.00000000
 0 0 1 0.00000000
      24


On Wed, Sep 9, 2015 at 10:52 PM, Gavin Abo <gsabo at crimson.ua.edu<mailto:gsabo at crimson.ua.edu>> wrote:
Did you send the wrong scfmbj.struct?  At least for me, "x nn" of WIEN2k 14.2 gives WARNINGS that the struct file is not okay.

username at computername:~/wiendata/scfmbj$ ls
scfmbj.struct
username at computername:~/wiendata/scfmbj$ x nn
 specify nn-bondlength factor: (usually=2) [and optionally dlimit, dstmax (about
  1.d-5, 20)]
2
 DSTMAX:   20.0000000000000
 iix,iiy,iiz           4           4           5   41.0521240000000
   41.0521240000000        51.3151550000000

    ATOM  1  Si         ATOM  2  Si
 RMT(  1)=2.21000 AND RMT(  2)=2.21000
 SUMS TO 4.42000  LT.  NN-DIST= 4.44402

    ATOM  2  Si         ATOM  1  Si
 RMT(  2)=2.21000 AND RMT(  1)=2.21000
 SUMS TO 4.42000  LT.  NN-DIST= 4.44402
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file

  NN created a new scfmbj.struct_nn file
NN created a new CASE.STRUCT_NN FILE
0.0u 0.0s 0:01.35 0.0% 0+0k 0+32io 0pf+0w


On 9/9/2015 8:48 AM, Muhammad Sajjad wrote:
Dear user
I computed Si BS for the structure (scfmbj.struct) attached herewith. When I apply strain (a+a*0.01, b, c-c*0.01) then symmetry changes (space group 1_P1). WIth this group calculations does not run every times QTLB error appears and I have done my best to apply each solution for it.
Secondly I got structure from wien2k examples. That works fine but when strain is applied then it behaves as a metal. Though this work has been done many times but I can not find my solution. I found VASP study but not wien2k study.
In VASP POSCAR is
cubic diamond
   5.50000000000000
     0.0000000000000000    0.4969432792132343    0.4969432792132343
     0.4969432792132343    0.0000000000000000    0.4969432792132343
     0.4969432792132343    0.4969432792132343    0.0000000000000000
   Si
     2
Direct
  0.8750000000000000  0.8750000000000000  0.8750000000000000
  0.1250000000000000  0.1250000000000000  0.1250000000000000

I changed this POSCAR to cif and used for wien2k (structure is attached TEST.struct) , then BS is correct, but after application of strain (1%) again it becomes metal.
I do not know how to apply strain in POSCAR.
Could you please guide me?

Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.

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--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.



--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.

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