SOC in AFM phase

Running Abinit Ground state
1

Dear Abinit users and developers,

If I am not wrong, it looks like there is no chance to apply SOC in magnetic phase. When SOC is activated with pawspnorb =1, it takes only nsppol =1 but with nspden =1. It does not accept nspden=2. Does it mean that SOC treatment is available only for non-magnetic case?

regards,
Rajesh

2

Hi Rajesh,

When SOC is on all bands are spinors and can be polarized or not. If the bands compensate in spin, and the density is not magnetized, you can leave the default nspden 1, otherwise you need the full vector magnetization (3 components) and nspden is 4 (density, mx, my, mz).

Nsppol 2 is only for the collinear (no SOC) case, then nspden is 2.

See the online doc with nspden, nspinor, nsppol for details.

Note that some things are not implemented for SOC + nspden 4 (magnetism with SOC) such as GGA phonons. The code should stop and complain if you try these combinations.

3

Hi!,

Thanks a lot. Yes, I tried with that combination SOC + nspden 4 and code stopped.