[Wien] about the LDA+U

[jan kunes]

Dear yushan,


> Dear users,
> does the LDA+U apply to the light transition metal. such as Ti, V, Cr and
> so on?

It depends on the compound. It should work reasonably in systems, where 
the d electrons are localized, e.g. oxides.

, and if the spin-up and spin-dn balance well, is the LDA+U
> full of physical significance?

No, LDA+U applies to ordered phase. If you have local moments as is 
typical for localized electrons, LDA+U provides a reasonable description 
of the ordered phase below T_c. Above T_c you still have local moments LM 
(Curie-Weiss susceptibility), but the fluctuate in time, i.e. this is not 
a non-magnetic NM state described by LDA or LDA+U. If you look at the 
occupation numbers <n> there is no difference between LM and NM, in 
both cases up=dn. The difference will be obvious from <N_up N_dn>. In NM
<n_up n_dn>=<n_up><n_dn> while in LM <n_up n_dn> << <n_up n_dn> due to 
Coulomb repulsion (LDA+U however can not capture this behavior since it is 
static method).

Jan


 > > yushan
> 
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