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<DIV><FONT face=Arial size=2>Hi</FONT></DIV>
<DIV><FONT face=Arial size=2>another possibility is to perform a constraint LDA
calculations to extract de U value</FONT></DIV>
<DIV><FONT face=Arial size=2>Please see:</FONT></DIV>
<DIV><FONT face=Arial size=2><A
href="http://www.wien2k.at/reg_user/textbooks/Constraint_U.pdf">http://www.wien2k.at/reg_user/textbooks/Constraint_U.pdf</A></FONT></DIV>
<DIV><FONT face=Arial size=2>by G. Madsen and P. Novak.</FONT></DIV>
<DIV><FONT face=Arial size=2>Regards</FONT></DIV>
<DIV><FONT face=Arial size=2>Ricardo</FONT></DIV>
<DIV>-------------------------------------------------------------------------<BR>-----
Ing. Quím. Ricardo Faccio<BR> <BR> Mail: Cryssmat-Lab., Cátedra de
Física, DETEMA<BR> Facultad de Química, Universidad de la
República<BR> Av. Gral. Flores 2124, C.C.
1157<BR> C.P. 11800, Montevideo,
Uruguay.<BR> E-mail: <A
href="mailto:rfaccio@fq.edu.uy">rfaccio@fq.edu.uy</A><BR> Phone: 598 2
9241860 Int.
109<BR>
598 2 9290705<BR> Fax: 598 2 9241906<BR>
Web: <A
href="http://cryssmat.fq.edu.uy/ricardo/ricardo.htm">http://cryssmat.fq.edu.uy/ricardo/ricardo.htm</A></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Igor.Djerdj@mat.ethz.ch href="mailto:Igor.Djerdj@mat.ethz.ch">Igor
Djerdj</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=wien@zeus.theochem.tuwien.ac.at
href="mailto:wien@zeus.theochem.tuwien.ac.at">wien@zeus.theochem.tuwien.ac.at</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, July 10, 2007 12:00
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Wien] LSDA+U</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Dear all,</FONT></DIV>
<DIV><FONT face=Arial size=2>Few months ago I submitted the post here
regarding the calculation of electronic structure of VOxHy compound. I
followed advices which I got here related to chooice of RMTs, RKmax, etc.. and
ended with compound which shows metallic behavior. According to DC
conductivity measurement the investigated compound is semiconducting with bang
gap of around 0.64 eV. Then I tried DFT calculation using LSDA+U approach, and
obtained this time Fermi level just slightly below the top of valence band and
the width of band gap strongly dependent of the value of U. For instance for
U=0.6 eV Eg=2.1 eV, U=4 eV, Eg=0.7 eV. The question is about reliability of
the applied method i.e. which value of U is recommendable for 3d electrons of
V? There are also changes in DOS with the change of U.</FONT></DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Igor</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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