I'm new to VASP and I'm trying to calculate the band structure of a bulk, nonmagnetic superconductor with a tetragonal crystal structure. I'm including spin-orbit coupling (SOC) in my calculation using LSORBIT=True.
The VASP manual mentions that LSORBIT=True also sets LNONCOLLINEAR=True automatically. However, my material is nonmagnetic. I'm confused about the following:
LNONCOLLINEAR: What does it mean by "noncollinear magnetic calculations"? Is this relevant for my nonmagnetic case?
MAGMOM: Since my material is superconducting and nonmagnetic, should I use the MAGMOM tag? if yes then how?
Any clarification or advice on setting up the INCAR file for this scenario would be greatly appreciated!
When you turn on spin-orbit coupling, the spin is no longer necessarily along the z axis, hence the "noncollinear" as in not collinear to the z axis.
In practice, you can still study nonmagnetic materials using LSORBIT=.TRUE.
Just put MAGMOM = 0 0 0 for the atom you're interested in. Be careful, unlike the collinear case, you have to put 3 numbers per atom for MAGMOM for the three spin directions sx,sy and sz.
hi Nilabja Kanti Sarkar
A no magnetic system with SOC calculation seems wired. Could u explain why you want this kind calculation. Is this materials really exists? or there is some special consideration.
Dear Nilabja Kanti Sarkar ,
MoS2 and some other members of the transition metal di-chalcogenide families do show a spin-up/down band splitting, although they are not magnetic. This effect can be reproduced only by including spin-orbit coupling for non-magnetic materials in the calculation. Without it, you would get the wrong results.
Regards,
Roberto
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