Hi,<br>I'm calculating NiO which is a canonical example of using LDA+U. Your speculation is right. The non-magnetic case is the one where I started from the converged LDA calculation. Is there a reason for that?<br><br>
<br><br>Yundi<br><br><br><br><div class="gmail_quote">On Thu, Feb 16, 2012 at 11:27 PM, Fecher, Gerhard <span dir="ltr"><<a href="mailto:fecher@uni-mainz.de">fecher@uni-mainz.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
I guess the non-magnetic solution is the one where you started from the converged LDA calculation<br>
and the magnetic one is the one where you started with LDA+U from scratch.<br>
<br>
You did not tell much about the system you are calculating and why you used LDA+U<br>
without knowing this, any thing for explanation just stays speculation.<br>
<br>
Ciao<br>
Gerhard<br>
<br>
<br>
<br>
====================================<br>
Dr. Gerhard H. Fecher<br>
Institut of Inorganic and Analytical Chemistry<br>
Johannes Gutenberg - University<br>
55099 Mainz<br>
________________________________________<br>
Von: <a href="mailto:wien-bounces@zeus.theochem.tuwien.ac.at">wien-bounces@zeus.theochem.tuwien.ac.at</a> [<a href="mailto:wien-bounces@zeus.theochem.tuwien.ac.at">wien-bounces@zeus.theochem.tuwien.ac.at</a>]&quot; im Auftrag von &quot;Yundi Quan [<a href="mailto:quanyundi@gmail.com">quanyundi@gmail.com</a>]<br>
Gesendet: Freitag, 17. Februar 2012 03:34<br>
An: A Mailing list for WIEN2k users<br>
Betreff: Re: [Wien] lda+u calculation<br>
<div class="im"><br>
Both cases are very converged. One gives magnetic solution. The other gives non-magnetic solution. The magnetic solution is slightly lower in energy.<br>
<br>
<br>
<br>
<br>
</div><div class="im">On Thu, Feb 16, 2012 at 4:48 PM, Laurence Marks <<a href="mailto:L-marks@northwestern.edu">L-marks@northwestern.edu</a><mailto:<a href="mailto:L-marks@northwestern.edu">L-marks@northwestern.edu</a>>> wrote:<br>
Maybe, or maybe not! If both cases are well converged, that means that<br>
for your approximations there are two locally stable spin states.<br>
Maybe this is real, maybe not, that is hard to say.<br>
<br>
</div>2012/2/16 Yundi Quan <<a href="mailto:quan@ms.physics.ucdavis.edu">quan@ms.physics.ucdavis.edu</a><mailto:<a href="mailto:quan@ms.physics.ucdavis.edu">quan@ms.physics.ucdavis.edu</a>>>:<br>
<div class="im">> You are right. The spin state is different in two cases. Applying U after a<br>
> scf calculation seems to tend to reduce the magnetic moments.<br>
><br>
><br>
><br>
><br>
><br>
><br>
><br>
><br>
</div>> On Thu, Feb 16, 2012 at 3:44 PM, Laurence Marks <<a href="mailto:L-marks@northwestern.edu">L-marks@northwestern.edu</a><mailto:<a href="mailto:L-marks@northwestern.edu">L-marks@northwestern.edu</a>>><br>
<div class="im">> wrote:<br>
>><br>
>> If all other things are the same, the lowest energy is correct<br>
>> (variational principle). Probably the spin state is different in the<br>
>> two cases.<br>
>><br>
>> But...please ensure that you really have both converged. Assuming that<br>
>> you have a recent version, do a "grep -e :MV case.scf" (with case<br>
>> replaced as appropriate). The % value should be small for true<br>
>> convergence; if it is not you do not have real convergence<br>
>> (technically it is called a "trap").<br>
>><br>
</div>>> 2012/2/16 Yundi Quan <<a href="mailto:quanyundi@gmail.com">quanyundi@gmail.com</a><mailto:<a href="mailto:quanyundi@gmail.com">quanyundi@gmail.com</a>>>:<br>
<div class="im">>> > Dear Sir/Madam,<br>
>> > When using LSDA+U, it is recommended to first do an LSDA caculation and<br>
>> > then<br>
>> > turn on U. I first did an LSDA calculation to convergence. Then, I<br>
>> > turned on<br>
>> > U. I also did a calculation by turning on U from the very beginning. I<br>
>> > compared the two results, and found that the later is lower in energy.<br>
>> > Which<br>
>> > one is correct?<br>
>> ><br>
>> ><br>
>> ><br>
>> ><br>
>> ><br>
>> > _______________________________________________<br>
>> > Wien mailing list<br>
</div>>> > <a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a><mailto:<a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a>><br>
<div class="im">>> > <a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien</a><br>
>> ><br>
>><br>
>><br>
>><br>
>> --<br>
>> Professor Laurence Marks<br>
>> Department of Materials Science and Engineering<br>
>> Northwestern University<br>
</div>>> <a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a><<a href="http://www.numis.northwestern.edu" target="_blank">http://www.numis.northwestern.edu</a>> <a href="tel:1-847-491-3996" value="+18474913996">1-847-491-3996</a><tel:<a href="tel:1-847-491-3996" value="+18474913996">1-847-491-3996</a>><br>
<div class="im">>> "Research is to see what everybody else has seen, and to think what<br>
>> nobody else has thought"<br>
>> Albert Szent-Gyorgi<br>
>> _______________________________________________<br>
>> Wien mailing list<br>
</div>>> <a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a><mailto:<a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a>><br>
<div class="im">>> <a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien</a><br>
><br>
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> _______________________________________________<br>
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</div>> <a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a><mailto:<a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a>><br>
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><br>
<br>
<br>
<br>
--<br>
Professor Laurence Marks<br>
Department of Materials Science and Engineering<br>
Northwestern University<br>
</div><a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a><<a href="http://www.numis.northwestern.edu" target="_blank">http://www.numis.northwestern.edu</a>> <a href="tel:1-847-491-3996" value="+18474913996">1-847-491-3996</a><tel:<a href="tel:1-847-491-3996" value="+18474913996">1-847-491-3996</a>><br>
<div class="im">"Research is to see what everybody else has seen, and to think what<br>
nobody else has thought"<br>
Albert Szent-Gyorgi<br>
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