DFT+U+SOC protocol?

[sondon]

Dear VASPians,

I am calculating some magnetic semiconductors (mostly 3/4d)
with DFT+U+SOC calculations according to couple of different recipes,
and the results are not so consistent...

My recipes are:

1. DFT+U+SOC all in one time (both LSORBIT and LDAU on)

2. DFT+U+SOC w/ Gamma only -> DFT+U+SOC w/ full K-points with CHGCAR from previous run (ICHARG = 1)

3-1. DFT+U -> DFT+U+SOC with CHGCAR from DFT+U (ICHARG = 1)
3-2. The same with 3-1 but ICHARG = 11

4-1. DFT+SOC -> DFT+U+SOC with CHGCAR from DFT+SOC (ICHARG = 1)
4-2 The same with 4-1 but ICHARG = 11

Which one would be most reliable?
Or is there any sort of protocol in VASP community?

I usually take the advantage of 4-1, because breaking
the symmetry before applying on-site repulsion seems more reasonable.
But sometimes the total energy is lower than that of 4-2,
and sometimes higher.

Another question:
During the calculations, I often encounter
"WARNING: grid for Broyden might be to small"
With adjusting mixing parameters, I resolve(?) this WARNINGS.

The results are, however, quite often different
with different mixing parameters combinations
(AMIX, AMIX_MAG, BMIX, BMIX_MAG, and sometimes AMIN).

Why do I have this WARNING, and how can I resolve this
(other than playing with mixing parameters)?
Or, what is the most reliable protocol for choosing mixing parameters
for DFT+U+SOC calculations of magnetic semiconductors?

Many thanks in advance :-)
<span class='smallblacktext'>[ Edited ]</span>

[support_vasp]

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