Dear All, thank you for the reply. i appreciate it.
i need U and J for a DMFT (homemade) code. this is the reason i would prefer to calculate U and J via Wannier formalism. Wannier functions i have calculated including d and p states/bands in order to have more localized states and i can have eigenvalues for self-consistent unperturbed (alpha=0) and perturbed (alpha finite) runs. i don`t understand if U and J calculated via derivates of eigenvalues respect occupancies of this two runs are correct. what is your opinion? i have the feeling that i should take care to extrapolate for different sizes of my system in what i`m doing. What do you mean by "very similar but another procedure"? thank you. Gianluca On Mon, Feb 15, 2010 at 10:10 AM, Dmitry Korotin <dmitry at korotin.name>wrote: > Dear Gianluca, > > > 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. > > If you are going to use U and J within original QE code you should > calculate U and J for atomic states as Matteo Cococcioni suggests. > > > 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? > > In the mentioned paper was used very similar but another procedure. > With use of the flag Hubbard_alpha() you are able to change occupancy > of a pure atomic (pseudoatomic) orbital. If Wannier function differs > noticeably from pure atomic state standart procedure is not suitable. > > -- > Best regards, > Dmitry Korotin > > Ph. D. Student, > Institute of Metal Physics > S. Kovalevskaya, 18 > 620041 Ekaterinburg GSP-170 > Russia > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100215/e7b14fd0/attachment.htm
