[Wien] When to apply the SOC and when not to apply SOC in the calculation?

[Qiwen]

Dear Wienk developers and users,

I recently done the calculations to this compound SrCuCoO4 - it is a double
perovskite hexagonal (I4/MMM) ceramic, with weak
ferromgantic/antiferromagnetic property.

I did only the spin polarized calculation as a part of the content for a
paper. Upon submitting the paper to a journal, a feedback to the
calculation part was saying that I didn't treat the Spin Orbit coupling and
the correlation effects in the calculation as I should for rare-earth
elements in DFT calculation.

This makes me think of the 2 question:
1. when is it appropriated to apply the SOC and when does it not needed in
the calculation?

２. Was the feedback correct that for all rare-earth element related
semiconductor compounds we have to apply the SOC and the +U(for the
correlation) even if it is not a correlated system?

I could only find previous discussion on how to apply SOC and/or LDA+U but
not when to apply so please pardon me if similar question have been
answered before.

Thank you very much for your time.

kind regards,
Wen
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20120811/0973e7b7/attachment.htm>