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
