[Pw_forum] constrained_magnetization

[Lorenzo Paulatto]

In data 02 giugno 2009 alle ore 14:58:15, chu-chun fu <chuchun.fu at cea.fr>  
ha scritto:

> Dear PWscf developers and users,
>
> I would like to know if there is any possibility to constrain the
> magnitud of magnetic moment of only one type of atoms in a
> 'multi-component' system, when using 'atomic constrained-magnetization' ?

Dear Chu Chun,
it looks to me like your question is a variant on the very popular "how  
can I fix atom X to have occupation Z". Unluckily there is no real  
solution to it, as in DFT (especially on a plane-wave basis set) there is  
no straitforward way to say to which atom a certain electron belongs.

Possible solutions include LDA+U and constrained DFT, which require some  
knowledge and practice to use correctly. the former is explained in detail  
in M. Cococcioni's PhD thesis which you can find on sissa web pages:  
<http://www.sissa.it/cm/phd.php>; I don't know if the latter is officialy  
supported in QE.

best regards


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Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
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