[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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20181105/3b9dfda1/attachment.html>