Problem in KPOINTS

[konda.physics@gmail.com]

Dear Admin,

I am calculating without spin-orbit and with spin-orbit coupling calculation for a rhombohedral structure with space group number 160. Surprisingly, I found different IBZKPT from without SOC to with SOC such as enhancing from 116 to 220. Kindly see the below INCAR and suggest me the solution

without SOC

Starting parameter:
ISTART = 0 ! 0 for scratch; 1 use old WAVECAR
ICHARG = 1 ! 1 use for old CHGCAR; 2 for superposition of atoms
! LCHARG = .FALSE.
! LWAVE = .FALSE.
NPAR = 4

Electronic minimization
ENCUT=400
EDIFF = 1E-06 stopping criterion
SIGMA = 0.1 width
ISMEAR = 0 smearing 0-Gaussian 1-Methfessel-Paxton -5-tetrahedron-Bl<C3><B6>chl
---------------------------------------------------------------------------------
with SOC INCAR

Starting parameter:
ISTART = 0 ! 0 for scratch; 1 use old WAVECAR
ICHARG = 1 ! 1 use for old CHGCAR; 2 for superposition of atoms
! LCHARG = .FALSE.
! LWAVE = .FALSE.
NPAR = 4

Electronic minimization
ENCUT=400
EDIFF = 1E-06 stopping criterion
SIGMA = 0.1 width
ISMEAR = 0 smearing 0-Gaussian 1-Methfessel-Paxton -5-tetrahedron-Bl<C3><B6>chl
LSORBIT= .TRUE.
MAGMOM = 12*0.0 !!!
VOSKOWN = 1

Thanks in advance.
Regards:
S Appalakondaiah
SKKU

[merzuk.kaltak]

Hello,

The number of k-points in the IRZ is doubled, because time-reversal symmetry for spin-orbit calculations coupling is not implemented.