<div class="MsoNormal">Thank you for your comments. I am sure you will be happy if know about the following website:</div> <div class="MsoNormal"><a href="http://www-als.lbl.gov/als/science/sci_archive/57rixs.html">http://www-als.lbl.gov/als/science/sci_archive/57rixs.html</a></div> <br><blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">For example, there is by no means a direct relation telling if U is zero then electrons are delocalised.<br><br>You may be partially right, but not that way. There is no experiment that is able to measure U and there is no method to calculate U ab-initio! There are only methods to estimate U from both experiment and calculation by some approximations.<br><br>Ciao<br>Gerhard<br><br><br>-----Ursprüngliche Nachricht-----<br>Von: wien-bounces@zeus.theochem.tuwien.ac.at im Auftrag von Saeid Jalali<br>Gesendet: Mi 26.07.2006 00:20<br>An: A Mailing list for WIEN2k
users<br>Betreff: Re: [Wien] LDA+U<br> <br> Performing careful experiment can answer if a system, i.e. in your case a pure metal, is highly correlated or not at a given thermodynamic state. If this were (not) so and you know it from experiment LDA+U is (not) necessary. If you do not know it and (or) would theoretically investigate (confirm) it, then performing LDA+U assuming U as an variable seems to be an appropriate tool. Since if you find zero value for U comparing your result with experiment, then you can confirm that it is not strongly correlated system. One can investigate utilizing the constraint method of calculating U value the degree of localization. If U is calculated to be zero then the system is predicted purely theoretically to be delocalized. Screening is a good point that you have touched it. But I suggest to be careful about your interpretation taking correct model into account:<br> The d/f-electrons interact either indirectly as described by
the RKKY model within the conduction electrons, where the spins of the d/f electrons are coupled together by the magnetization induced in the conduction electrons, or directly with the other delocalized conduction electrons in the vicinity of the Fermi level as described by the Kondo model, where spin-flip scattering between magnetic d/f electrons and nonmagnetic conduction electrons play more important role than the indirect RKKY interactions of d/f moments.<br> If you would correctly interpreter your result you may know about these two model Hamiltonian reading many-body text books.<br> <br> Say hello to everybody there.<br> <br> hamad@fhi-berlin.mpg.de wrote: Thanks Saeid,<br> but as we know that LDA+U is needed for systems with strong<br>electron-electron interaction, this appears in transition metal<br>oxides that causes the wrong prediction of metallic type rather<br>than insulator "Mott-Hubbard insulators".<br>So what about pure
transition-metal systems, I think in this case the<br>screening effect reduces the electron-electron interaction and in this<br>case LDA+U is not needed. Am I right??<br>Thanks<br>Bothina<br><br><br>> Yes, it is meaningful. LDA+U is intended to improve L(S)DA weakness<br>> of treating strongly correlated f/d density of states. Magnetic<br>> systems will be non-magnetic in higher temperature. In higher<br>> temperatur,<br> those systems again have their d/f states which need<br>> (sometimes) improvement including LDA+U. However, in practice as<br>> mentioned in the textbook it is necessary to be treated magnetically<br>> even non-magnetic systems. This can be done as discussed in the<br>> usersguide and frequently in the list using runsp_c_lapw script<br>> (instead of run_lapw) to constrain to be zero the magnetic moment:<br>> http://zeus.theochem.tuwien.ac.at/pipermail/wien/2006-March/006863.html<br>>
http://zeus.theochem.tuwien.ac.at/pipermail/wien/2005-October/005994.html<br>> http://zeus.theochem.tuwien.ac.at/pipermail/wien/2004-April/002425.html<br>> http://zeus.theochem.tuwien.ac.at/pipermail/wien/2005-December/006304.html<br>><br>> Bothina Hamad wrote: Dear Wien users,<br>> I want to ask if is it possible to use LDA+U method in<br>> a nonspin-polarized calculations? does it have a meaning?<br>> Best regards<br>> Bothina<br>> --<br>> -----------------------------------------------------------------------<br>> Bothina Hamad Phone: (+49 30) 8413-4851<br>> Fritz-Haber-Institut Fax: (+49 30) 8413-4701<br>> Van't-Hoff-Straße 19 WWW: www.fhi-berlin.mpg.de<br>> D-14195 Berlin (Germany) E-Mail: hamad@fhi-berlin.mpg.de<br>> -----------------------------------------------------------------------<br>> _______________________________________________<br>> Wien mailing
list<br>> Wien@zeus.theochem.tuwien.ac.at<br>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br>><br>><br>><br>> Sincerely yours,<br>> S. Jalali.<br>> /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/<br>> Saeid Jalali Asadabadi,<br>> Department of Physics, Faculty of Science,<br>> University of Isfahan (UI), Hezar Gerib Avenue,<br>> 81744 Isfahan, Iran.<br>> Phones:<br>> Dep. of Phys. :+98-0311-793 2435<br>> Office :+98-0311-793 2430<br>> Fax No. :+98-0311-793 2409<br>> E-mail :s_jalali_a@yahoo.com<br>> www :http://www.ui.ac.ir<br>> /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/<br>><br>> ---------------------------------<br>> Groups are talking. We´re listening. Check out the handy changes to<br>> Yahoo! Groups. _______________________________________________<br>> Wien mailing list<br>> Wien@zeus.theochem.tuwien.ac.at<br>>
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br>><br><br>_______________________________________________<br>Wien mailing list<br>Wien@zeus.theochem.tuwien.ac.at<br>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br><br><br><br>Sincerely yours,<br>S. Jalali.<br>/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/<br>Saeid Jalali Asadabadi,<br>Department of Physics, Faculty of Science,<br>University of Isfahan (UI), Hezar Gerib Avenue,<br>81744 Isfahan, Iran.<br>Phones:<br>Dep. of Phys. :+98-0311-793 2435<br>Office :+98-0311-793 2430<br>Fax No. :+98-0311-793 2409<br>E-mail :s_jalali_a@yahoo.com<br>www :http://www.ui.ac.ir<br>/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/<br> __________________________________________________<br>Do You Yahoo!?<br>Tired of spam? Yahoo! Mail has the best spam protection around <br>http://mail.yahoo.com <br><br>_______________________________________________<br>Wien
mailing list<br>Wien@zeus.theochem.tuwien.ac.at<br>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br></blockquote><br><BR><BR>Sincerely yours,<br>S. Jalali.<br>/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/<br>Saeid Jalali Asadabadi,<br>Department of Physics, Faculty of Science,<br>University of Isfahan (UI), Hezar Gerib Avenue,<br>81744 Isfahan, Iran.<br>Phones:<br>Dep. of Phys. :+98-0311-793 2435<br>Office :+98-0311-793 2430<br>Fax No. :+98-0311-793 2409<br>E-mail :s_jalali_a@yahoo.com<br>www :http://www.ui.ac.ir<br>/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/<p> 
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