Dear Professor Blaha,<br>Thank you very much for the detailed explanation. I think I have gained a lot from your reply.<br>(PS yes there is this Eu rare-earth element in my compound).<br><br>Much appreciated your time.<br>
<br>Kind regards,<br>Wen<br><br><div class="gmail_quote">On Sat, Aug 11, 2012 at 3:56 PM, Peter Blaha <span dir="ltr"><<a href="mailto:pblaha@theochem.tuwien.ac.at" target="_blank">pblaha@theochem.tuwien.ac.at</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hm, I don't know if I understand everything. There's no rare-earth element in your<br>
compound ???<br>
<br>
Anyway:<br>
<br>
Yes, for practically all 3d- transition metal oxides (Cu, Co-oxide like yours) going<br>
beyond stadard DFT is necessary. LDA+U is the "simplest" of these methods and quite<br>
good for these systems. In addition, magnetism (FM or more likely some AFM configuration)<br>
needs to be considered.<br>
<br>
SOC: The effects of SOC are usually larger for heavier elements, like 5d-series or 5f actinides.<br>
Nevertheless, in particular together with magnetism (orbital moments) even for 3d-elements<br>
(Co is famous for this) it can sometimes be an important ingredient, but usually SOC does not<br>
change the results for 3d-systems qualitatively, but only quantitatively<br>
<br>
For rare-earth systems, usually LDA+U is "more important" than SOC, but of course also SOC<br>
can be important (again, in particular for magnetism).<br>
<br>
These are just rough guidelines. One never knows for a particular system unless one tries it ....<br>
<br>
Am 11.08.2012 07:04, schrieb Qiwen:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
Dear Wienk developers and users,<br>
<br>
I recently done the calculations to this compound SrCuCoO4 - it is a double perovskite hexagonal (I4/MMM) ceramic, with weak ferromgantic/antiferromagnetic property.<br>
<br>
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<br>
didn't treat the Spin Orbit coupling and the correlation effects in the calculation as I should for rare-earth elements in DFT calculation.<br>
<br>
This makes me think of the 2 question:<br>
1. when is it appropriated to apply the SOC and when does it not needed in the calculation?<br>
<br>
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<br>
correlated system?<br>
<br>
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.<br>
<br>
Thank you very much for your time.<br>
<br>
kind regards,<br>
Wen<br>
<br>
<br></div></div>
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</blockquote>
<br>
-- <br>
------------------------------<u></u>-----------<br>
Peter Blaha<br>
Inst. Materials Chemistry, TU Vienna<br>
Getreidemarkt 9, A-1060 Vienna, Austria<br>
Tel: <a href="tel:%2B43-1-5880115671" value="+4315880115671" target="_blank">+43-1-5880115671</a><br>
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