[Wien] Fermi surface not 4 fold symmetric for a cubic material with space group Pm3m

[Anup Shakya]

Dear All,
I have done non-magnetic GGA+SOC+U calculations with U and J for a material
containing rare earth element. Without SOC and U the Fermi surface is 4
fold symmetric but when I performed GGA+SOC+U calculations the Fermi
surface is not 4 fold symmetric. Before applying SOC the position of the
atoms were as follows:
Atom X Mult =1 0.0 0.0 0.0
Atom Y Mult 6 0.207 0.5 0.5
After SOC the a,b,c values and the symmetry i.e, Pm3m is the same as before
but now the Y positions has split into two non-equivalent atoms as shown
below.
Atom Y 2 Mult 4 0.207 0.5 0.5
Atom Y 3 Mult 2 0.5 0.5 0.207.
The position and the multiplicity of X atom is unchanged. I think probably
because of SOC the equivalent atoms have changed into non-equivalent atoms
and led to the anisotropy in the band structure along the G-X and X-G
direction and also 4 fold symmetry is not there in the Fermi surface
calculations. But if I want to compare the obtained band structure or the
Fermi surface with the ARPES results then it doesn't make sense because the
Fermi surface should be 4 fold symmetric. I do not know what to do. If you
need any more information then please let me know. Please provide some
suggestions as to preserve the 4 fold symmetry along with GGA+SOC+U
calculations. Any suggestion would be very much valuable for me.

Sincerely,
Anup Pradhan Sakhya,
TIFR, India

[Anup Shakya]

Dear Prof Blaha,

I have performed non magnetic spin polarized calculations using
runsp_c_lapw -orb. I have not shifted the k-mesh for FS calculations. I
couldn't use the command x kgen -so for FS calculations as I got the
following error.
forrtl: severe (24): end of file during read, unit 20, file/case.ksym
error command: /home/kbmaiti/wien2k/kgen kgen.def failed.
So I used x kgen 30000 kpoints no shift
x lapw1 - up
x lapwso
cp case.outputso case.output1
x lapw2 - so - fermi
I don't think there is any problem with the FS calculations as it is
matching with the bandstructure calculations. The only problem is the
lowering of the symmetry with SOC from 48 to 16 number of symmetry
operations though the structure is still cubic for magnetization direction
along 0 0 1 axis. Due to this lowering of symmetry the band structure plot
along G-X and X-G is different. But experimentally if one measures the
bandstructure or the FS of this material it should be the same because
experimentally the structure is cubic. So my question is whether non
magnetic spin polarized calculations with U and SOC is at all reliable to
match or analyze the experimental results. The only reason for doing non
magnetic spin polarized calculations was to take into account the strong
correlation of R 4f states. I am confused. Please clarify.

Sincerely,
Anup Pradhan Sakhya

Post by Anup Shakya
Dear All,
I have done non-magnetic GGA+SOC+U calculations with U and J for a
material containing rare earth element. Without SOC and U the Fermi surface
is 4 fold symmetric but when I performed GGA+SOC+U calculations the Fermi
surface is not 4 fold symmetric. Before applying SOC the position of the
Atom X Mult =1 0.0 0.0 0.0
Atom Y Mult 6 0.207 0.5 0.5
After SOC the a,b,c values and the symmetry i.e, Pm3m is the same as
before but now the Y positions has split into two non-equivalent atoms as
shown below.
Atom Y 2 Mult 4 0.207 0.5 0.5
Atom Y 3 Mult 2 0.5 0.5 0.207.
The position and the multiplicity of X atom is unchanged. I think probably
because of SOC the equivalent atoms have changed into non-equivalent atoms
and led to the anisotropy in the band structure along the G-X and X-G
direction and also 4 fold symmetry is not there in the Fermi surface
calculations. But if I want to compare the obtained band structure or the
Fermi surface with the ARPES results then it doesn't make sense because the
Fermi surface should be 4 fold symmetric. I do not know what to do. If you
need any more information then please let me know. Please provide some
suggestions as to preserve the 4 fold symmetry along with GGA+SOC+U
calculations. Any suggestion would be very much valuable for me.
Sincerely,
Anup Pradhan Sakhya,
TIFR, India

[Anup Shakya]

Dear All,

I have not got any suggestion for the question. If anyone can give me some
suggestions that would be great. If you need more information about the
structure or the problem then please let me know.

Sincerely,
Anup Pradhan Sakhya (Ph.D.)
Visiting Post-Doctoral Fellow
DCMP&MS, TIFR, Mumbai

[Anup Shakya]

Dear Prof. Blaha,

I have used the following structure file for non-magnetic calculations with
U and J. The U and J was used for the Sm atom and the calculations were
fine. I performed the calculations using runsp_c_lapw -orb -p.

Title
P LATTICE,NONEQUIV.ATOMS: 2 221 Pm-3m
MODE OF CALC=RELA unit=ang
7.812131 7.812131 7.812131 90.000000 90.000000 90.000000
ATOM 1: X=0.00000000 Y=0.00000000 Z=0.00000000
MULT= 1 ISPLIT= 2
Sm1 NPT= 781 R0=0.00001000 RMT= 2.50000 Z: 62.0
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
0.0000000 1.0000000 0.0000000
0.0000000 0.0000000 1.0000000
ATOM -2: X=0.20700000 Y=0.50000000 Z=0.50000000
MULT= 6 ISPLIT=-2
-2: X=0.79300000 Y=0.50000000 Z=0.50000000
-2: X=0.50000000 Y=0.20700000 Z=0.50000000
-2: X=0.50000000 Y=0.79300000 Z=0.50000000
-2: X=0.50000000 Y=0.50000000 Z=0.20700000
-2: X=0.50000000 Y=0.50000000 Z=0.79300000
B 1 NPT= 781 R0=0.00010000 RMT= 1.61 Z: 5.0
LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
0.0000000 1.0000000 0.0000000
-1.0000000 0.0000000 0.0000000
48 NUMBER OF SYMMETRY OPERATIONS

After this I performed GGA+SOC+U calculations. The direction of
magnetization is chosen along 001. (Even if I change the direction of
magnetization to 010 or 100 the structure files looks the same as below).

Title s-o calc. M|| 0.00 0.00 1.00
P 3 221
RELA
7.812131 7.812131 7.812131 90.000000 90.000000 90.000000
ATOM -1: X=0.00000000 Y=0.00000000 Z=0.00000000
MULT= 1 ISPLIT=-2
Sm1 NPT= 781 R0=.000010000 RMT= 2.50000 Z: 62.00000
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
0.0000000 1.0000000 0.0000000
0.0000000 0.0000000 1.0000000
ATOM -2: X=0.20700000 Y=0.50000000 Z=0.50000000
MULT= 4 ISPLIT= 8
-2: X=0.79300000 Y=0.50000000 Z=0.50000000
-2: X=0.50000000 Y=0.20700000 Z=0.50000000
-2: X=0.50000000 Y=0.79300000 Z=0.50000000
B 1 NPT= 781 R0=.000100000 RMT= 1.61000 Z: 5.00000
LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
0.0000000 1.0000000 0.0000000
-1.0000000 0.0000000 0.0000000
ATOM -3: X=0.50000000 Y=0.50000000 Z=0.20700000
MULT= 2 ISPLIT=-2
-3: X=0.50000000 Y=0.50000000 Z=0.79300000
B 1 NPT= 781 R0=.000100000 RMT= 1.61000 Z: 5.00000
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
0.0000000 1.0000000 0.0000000
0.0000000 0.0000000 1.0000000
16 NUMBER OF SYMMETRY OPERATIONS
1 0 0 0.0000000
0 1 0 0.0000000
0 0 1 0.0000000
The command that I used is
initso_lapw
Magnetization direction 0 0 1, Emax default 5 Ryd
-->Add RLO for NONE, ALL, CHOOSE elements? (N/a/c) : c
p-Energy parameters for Sm1 atom is :
1 -1.58 0.002 CONT 1
1 0.30 0.000 CONT 1
No RLO chosen for B atom
In spinpolarized case SO may reduce symmetry.
The program symmetso dedects the proper symmetry and creates new struct and
input files. (Note, equivalent atoms could become inequivalent in some
cases).
Do you have a spinpolarized case (and want to run symmetso) ? (y/N)y
90.0000000000000 90.0000000000000 1.57079632679490 T
1.00000000000000 0.000000000000000E+000 0.000000000000000E+000
6.123233995736766E-017 1.00000000000000 0.000000000000000E+000
6.123233995736766E-017 6.123233995736766E-017 1.00000000000000
0.1u 0.0s 0:00.27 74.0% 0+0k 2232+4776io 6pf+0w
emacs: Command not found.
A new structure for SO calculations has been created (_so).
If you commit it will create new smb6UJ7eV.struct, in1(c), in2c, inc,
clmsum/up/dn, vspup/dn and vnsup/dn files. (Please SAVE any previous
calculations)
NOTE: Files for -orb (smb6UJ7eV.indm(c),inorb,dmatup/dn) must be adapted
manually
Do you want to use the new structure for SO calculations ? (y/N)y
We run KGEN to generate a new kmesh for the SO calculation:
Number of Kpoint in smb6UJ7eV.klist is : 1000
Spinorbit is now ready to run.
Then I used the following command:
runsp_c_lapw -so -orb -p.

If you need any more information, then please let me know. Looking forward
to hearing from you.

Sincerely,
Anup Pradhan Sakhya (Ph.D.)
Visiting Post-Doctoral Fellow
DCMP&MS, TIFR, Mumbai

[Gavin Abo]

A couple comments:

1) To remove the "emacs: Command not found", you could install emacs. 
For example, something like "sudo apt-get install emacs25" on Ubuntu [
https://askubuntu.com/questions/851633/emacs-25-on-ubuntu-16-10 ].  Or
in .bashrc, you could change

export EDITOR="emacs"

to another text editor like vi (or gedit, nano, etc.)[
https://en.wikipedia.org/wiki/Category:Linux_text_editors ]

export EDITOR="vi"

2) WIEN2k 18.2 should have:

***@computername:~$ cat $WIENROOT/WIEN2k_VERSION
WIEN2k_18.2 (Release 17/7/2018)
***@computername:~$ grep "The program symmetso" $WIENROOT/initso_lapw
The program symmetso detects the proper symmetry and creates new struct and

The misspelled "dedects" indicates that you are likely using an older
WIEN2k version.  Older versions had some issues with or improvements
made for spin orbit (SO) calculations. Full details can be found on the
WIEN2k updates page [
http://susi.theochem.tuwien.ac.at/reg_user/updates/ ].  For example:

VERSION_18.1: 1.6.2018

...

SRC_symmetso: extensive fixes for writing correct files with modified
symmetry. Corrects also r2v, vresp files (if present); tol=1.e-4

Post by Anup Shakya
Dear Prof. Blaha,
I have used the following structure file for non-magnetic calculations
with U and J. The U and J was used for the Sm atom and the
calculations were fine. I performed the calculations using
runsp_c_lapw -orb -p.
Title
P   LATTICE,NONEQUIV.ATOMS:  2 221 Pm-3m
MODE OF CALC=RELA unit=ang
  7.812131  7.812131  7.812131 90.000000 90.000000 90.000000
ATOM   1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 2
Sm1        NPT=  781  R0=0.00001000 RMT= 2.50000   Z: 62.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.20700000 Y=0.50000000 Z=0.50000000
          MULT= 6          ISPLIT=-2
      -2: X=0.79300000 Y=0.50000000 Z=0.50000000
      -2: X=0.50000000 Y=0.20700000 Z=0.50000000
      -2: X=0.50000000 Y=0.79300000 Z=0.50000000
      -2: X=0.50000000 Y=0.50000000 Z=0.20700000
      -2: X=0.50000000 Y=0.50000000 Z=0.79300000
B 1        NPT=  781  R0=0.00010000 RMT= 1.61      Z:  5.0
LOCAL ROT MATRIX:    0.0000000 0.0000000 1.0000000
                     0.0000000 1.0000000 0.0000000
                    -1.0000000 0.0000000 0.0000000
  48      NUMBER OF SYMMETRY OPERATIONS
After this I performed GGA+SOC+U calculations. The direction of
magnetization is chosen along 001. (Even if I change the direction of
magnetization to 010 or 100 the structure files looks the same as below).
Title                                    s-o calc. M||  0.00  0.00  1.00
P                            3 221
             RELA
  7.812131  7.812131  7.812131 90.000000 90.000000 90.000000
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT=-2
Sm1        NPT=  781  R0=.000010000 RMT= 2.50000   Z:  62.00000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.20700000 Y=0.50000000 Z=0.50000000
          MULT= 4          ISPLIT= 8
      -2: X=0.79300000 Y=0.50000000 Z=0.50000000
      -2: X=0.50000000 Y=0.20700000 Z=0.50000000
      -2: X=0.50000000 Y=0.79300000 Z=0.50000000
B 1        NPT=  781  R0=.000100000 RMT= 1.61000   Z:   5.00000
LOCAL ROT MATRIX:    0.0000000 0.0000000 1.0000000
                     0.0000000 1.0000000 0.0000000
                    -1.0000000 0.0000000 0.0000000
ATOM  -3: X=0.50000000 Y=0.50000000 Z=0.20700000
          MULT= 2          ISPLIT=-2
      -3: X=0.50000000 Y=0.50000000 Z=0.79300000
B 1        NPT=  781  R0=.000100000 RMT= 1.61000   Z:   5.00000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
  16      NUMBER OF SYMMETRY OPERATIONS
 1 0 0 0.0000000
 0 1 0 0.0000000
 0 0 1 0.0000000
The command that I used is
initso_lapw
Magnetization direction  0 0 1, Emax default 5 Ryd
-->Add RLO for NONE, ALL, CHOOSE elements? (N/a/c) : c
 1   -1.58      0.002 CONT 1
 1    0.30      0.000 CONT 1
No RLO chosen for B atom
In spinpolarized case SO may reduce symmetry.
The program symmetso dedects the proper symmetry and creates new
struct and input files. (Note, equivalent atoms could become
inequivalent in some cases).
Do you have a spinpolarized case (and want to run symmetso) ? (y/N)y
   90.0000000000000        90.0000000000000 1.57079632679490      T
   1.00000000000000       0.000000000000000E+000 0.000000000000000E+000
  6.123233995736766E-017   1.00000000000000 0.000000000000000E+000
  6.123233995736766E-017  6.123233995736766E-017 1.00000000000000
0.1u 0.0s 0:00.27 74.0% 0+0k 2232+4776io 6pf+0w
emacs: Command not found.
 A new structure for SO calculations has been created (_so).
 If you commit it will create new smb6UJ7eV.struct, in1(c), in2c, inc,
 clmsum/up/dn, vspup/dn and vnsup/dn files. (Please SAVE any previous
 calculations)
NOTE: Files for -orb (smb6UJ7eV.indm(c),inorb,dmatup/dn) must be
adapted manually
Do you want to use the new structure for SO calculations ? (y/N)y
Number of Kpoint in smb6UJ7eV.klist is : 1000
Spinorbit is now ready to run.
runsp_c_lapw -so -orb -p.
If you need any more information, then please let me know. Looking
forward to hearing from you.
Sincerely,
Anup Pradhan Sakhya (Ph.D.)
Visiting Post-Doctoral Fellow
DCMP&MS, TIFR, Mumbai