[Wien] LDA+U

[Hua Wu]

Consider two points:
1. whether the xz and yz are degenerate and form a doublet?
if true, for your d2 system big U may stabilize this doublet but 
leave xy empty and then get a energy gap.

2. check carefully the rotation matrix and make sure what type of
orbital you are really looking at.

regards -- H. Wu
On Thursday 20 April 2006 18:20, Tulika Maitra wrote:
> Dear Wien-users,
>
> I have encountered the following problem in my LDA+U
> calculation. I have a compound with a distorted octahedron
> (compressed along z-axis) with the transition metal ion in
> 3d^2 configuration.
> I used U_eff=U-J as suggested in the userguide and I expected
> to get a fully polarized d_xy orbital which should get pushed
> down with high U value. With WIEN2K'05 version I am not
> getting this whereas with WIEN2K'03 version (finite U and J) I
> get that. I have a non-identity local rotation matrix, so I
> have done the rotation using QTL to project the density of
> states in the global co-ordinate system.
>
>
> Thanking you for any help.
>
> -best regards
> Tulika Maitra
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-- 
Dr. Hua WU

II. Physikalisches Institut
der Uni. zu Koeln,
Zuelpicher Str. 77,
D-50937 Koeln
Germany

Email: wu at ph2.uni-koeln.de
Tel: +49-221-4703599
Fax: +49-221-4705178