[Wien] Unit of :ORBxx

[Pavel Novak]

large U is there to stabilize the starting configuration. For iron 0.3-0.7
Ry is reasonable. You can try to calculate U, but be aware that you'll get
another 'reasonable' value. There is no 'best' U as what we attempt with
LDA+U is to map the many body problem on a sinle particle one.

Regards
pavel Novak

_________________________________________________
Dr. Pavel Novak
Department of Magnetism and Superconductivity
Institute of Physics AS CR
Cukrovarnicka 10, 162 53 Praha 6, Czech Republic
tel: +420 2 20 318 532
e-mail: novakp at fzu.cz

On Tue, 5 Dec 2006, Chiung-Yuan Lin wrote:

> Dear Dr Novak,
>   I did 1/ already. I can try 2/. But I don't understand the part
> "LDA+U with large U" in 3/.
> Instead of putting a large U by hand, shouldn't one determine U using the
> "constraint LDA calculations"?
>
> Thanks,
> Chiung-Yuan
>
> On 12/5/06, Pavel Novak <novakp at fzu.cz> wrote:
> > Dear colleagues,
> >
> > here is the receipt to get desirable high orbital momentum:
> >
> > 1/ converge the LSDA calculation
> >
> > 2/ construct starting density matrix by hand, occupying fully all five
> > majority spin states (put 1 on the diagonal) and ML=2 minority spin state.
> > Leave remaining minority spin states empty.
> >
> > 3/ Run LDA+U +s-o calculation with reasonably large U (e.g. 0.7 Ry).
> >
> > The starting configuration will survive the selfconsistent procedure so
> > that resulting orbital moment will be equal to 2.
> >
> > Regards
> > Pavel Novak
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