[Pw_forum] CuO, LDA+U, Pseudopots, etc.

Nicola Marzari marzari at MIT.EDU
Fri Dec 14 04:17:34 CET 2007

Agostino Migliore wrote:
> Hello
> Also independently of this specific problem, I use the occasion to say
> that sometimes, with finite U, the code gets trapped in local minima for
> some values of the "mixing_beta" parameter.

Did you characterize the local minimum, by any chance ? The system
is fairly simple (on one side, 5 d electrons, say all up, and
on the other side, 6 d electrons). Do you have a sense if the
additional minimum is due to some long range ferro vs. antiferro
coupling between the two ions (i.e. 5 up on one side, and 5 up and
1 down, vs 5 up, 5 down and 1 up), or if the minorit spin on the ferric
ion splits in two or three orbtials with fractional occupations ?


Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu

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