<div dir="ltr">Dear Prof. Blaha,<div><br></div><div> Thank you very much for you reply on this. Actually I did relax the structure under GGA+U approximation. Then took two approaches. In one case I did SCF calculation under GGA+U with relaxed structure and added SOC afterthat. In other case I took relaxed structure and did GGA+U+SOC calculation.</div><div>Which gave me two different electronic structure for the same relaxed structure.</div><div><br></div><div>So I have to take lowest energy structure.</div><div><br></div><div>Thanking you and regards,</div><div><br></div><div>Santu Baidya</div><div><br></div><div><br></div><div><br></div><div><br></div><img width="0" height="0" class="mailtrack-img" src="https://mailtrack.io/trace/mail/134221eee5caa12078cb0a8d6a8b4a4d827a12f7.png"></div><div class="gmail_extra"><br><div class="gmail_quote">On 23 November 2015 at 18:58, 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">It is well know that GGA+U calculations can end up in different states (see previous posts).<br>
<br>
If you have used the same parameters, you should use the total energies of the two calculations and the one with lower energy should be the better one (but not necessarily the best !)<br>
<br>
In any case, I always recommend:<br>
<br>
First do a standard GGA calculation (also check forces, if they are small).<br>
Then add SO and do a GGA+SO calculation (if you really have heavy elements?)<br>
x lapwdm -up -so to generate density matrices<br>
<br>
and finally add the "U" and do GGA+so+U<br>
<br>
There is, however, no guarantee that you find the lowest energy ground state ! Sometimes it is good to start with a smaller U-value than anticipated.<br>
Sometimes you may do a structure relaxation at the GGA-level and use this structure,<br>
or a structure relaxation at GGA+U (no SO).<br>
<br>
If SO is not a major effect, I'd first do everything without SO.<br>
<br>
-------------------<br>
>From these advices you can see that there is not a unique and save way, which works in all cases.<span class=""><br>
<br>
<br>
<br>
On 11/23/2015 12:10 PM, Santu Baidya wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
Dear Prof. Blaha and wien2k users,<br>
<br>
I use wien2k version WIEN2k_14.1. Recently I did spin-orbit<br>
coupling calculation under GGA+U+SOC approximation with two different<br>
approaches- one starting from collinear ground state and another<br>
starting from scratch (random wavefunction). Two approaches give me<br>
completely different results -metal and insulator.<br>
<br>
Please tell me which approach should I accept as solution.<br>
<br>
I look forward to get reply.<br>
<br>
Thanking you,<br>
<br>
Santu Baidya<br>
University of Duisburg-Essen<br>
Duisburg<br>
<br>
<br>
<br>
<br></span>
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