Gianluca Giovannetti wrote: > Dear Matteo, > > thank you for the link. > now it is fine. > i can calculate U with your scheme. :-) > > what about J ? >
Dear Gianluca the formal extension of the linear-response machinery to compute U to a spin-resolved case (using magnetization instead of occupations) doesn't work to obtain J. this is at least my experience. regards, Matteo > cheers, > > Gianluca > > On Mon, Feb 15, 2010 at 2:45 AM, Matteo Cococcioni <matteo at umn.edu > <mailto:matteo at umn.edu>> wrote: > > > Dear Gianluca, > > here is the link to a tutorial on how to compute the U: > > http://media.quantum-espresso.org/santa_barbara_2009_07/index.php > > This method uses the atomic occupations defined as in the PRB '05 > paper > you refer to in your email. > > For sure one could use Wannier functions ainstead of atomic orbitals. > HoweverI have no direct experience with that > so I cannot tell you how to do this in practice. > > regards, > > Matteo > > Gianluca Giovannetti wrote: > > > Dear All, > > > > i would like to calculate the U and J for a given material Fe based. > > I can do LDA+U calculations without problems is such system > using PW. > > > > The paper "Phys. Rev. B 71, 035105 (2005)" well explains how to > > calculate the parameter U. > > i have however troubles in setting the input files to do the > calculations. > > could some examples be provided? > > > > I have also another question. > > > > In the current distribution of PW in the directory PP there is a > file > > wannier_ham.f90. > > I believe it is referring to the paper: > > > > http://xxx.lanl.gov/pdf/0801.3500 > > > > The subroutines are reading wfs and eigenvalues of a given > > self-consistent calculation and they calculate the Hamiltonian in > > Wannier basis set. > > This gives the possibility to calculate on-site energy of given > d states. > > If now we change the occupancy at a given site by the flag > > Hubbard_alpha() and we recalculate the Hamiltonian in Wannier basis > > set for such self-consistent calculation, the variation of > eigenvalues > > respect to the occupations should give the U and J parameters. > > Is this correct? > > Is this the procedure used in the mentioned paper? > > > > thank you. > > > > cheers, > > > > Gianluca > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org> > > http://www.democritos.it/mailman/listinfo/pw_forum > > > > > -- > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > Matteo Cococcioni > Department of Chemical Engineering and Materials Science, > University of Minnesota > 421 Washington Av. SE > Minneapolis, MN 55455 > Tel. +1 612 624 9056 Fax +1 612 626 7246 > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org> > http://www.democritos.it/mailman/listinfo/pw_forum > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >