[Pw_forum] multiple-manifold DFT+U on a single atom

[Burak Himmetoglu]

Hi Deyu,

I have recently implemented a capability in the code that allows for using
Hubbard U on two orbital manifolds per atom (e.g. d and s states of
transition metals). If you are interested I can send you the code.

Regards

Burak Himmetoglu
Post-doctoral associate
Department of Chemical Engineering and Materials Sciecne
University of Minnesota,
421 Washington Av. SE
Minneapolis, MN 55455

On Mon, Jan 30, 2012 at 10:25 AM, Deyu Lu <deyulu at yahoo.com> wrote:

> Dear all:
>          I'm interested in doing DFT+U calculation on a single atom with
> multiple
> manifolds, and I'm wondering whether the code is available in some
> developmental stage.
> To be more specific, I'm looking at small Ce clusters and want to
> understand how linear
> response U of Ce changes according to the local chemical environment,
> e.g., valence state
> and spin state, etc. If I use only Ce 4f, I found chi0 and chi matrices
> don't obey sum rule,
> and in some cases, an eigenmode of chi0 and chi can be clearly identified
> corresponding to
> a uniform potential perturbation with a small negative eigenvalue. This
> means there is an exchange
> of the induced charge density between the 4f manifold and the background.
> By looking at PDOS, a non-negligible  4f-5d and 4f-6s hybridization are
> found right at LUMO,
> however, the hybridization with nearby O 2p seems to be weaker. In order
> to eliminate this error
> during the chi0 and chi inversion and
> obtain more accurate estimate on U, it makes sense to me to add Ce 5d and
> 6s. This modification
> is not quite obvious in set_hubbard_l.f90 and tabd.f90, since these
> subroutines assume one channel
> per atom type.
>
>          Best regards,
>          Deyu Lu
>
> ************************************************
> Deyu Lu
> Assistant Physicist, Theory & Computation Group
> the Center for Functional Nanomaterials
> Rm 1002, Building 735, Brookhaven National Lab
> Upton, NY, 11973
> webpage: http://www.bnl.gov/cfn/people/Deyu_Lu.asp
> ************************************************
>
>
>
>
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