[Wien] LDA+U

[Stefaan Cottenier]

> I am doing LDA+U calculations for FeO. It seems if I use the AMF
> method, the total energy with LDA+U is lower than that of LDA, but if
> I use SIC method, the result is opposite.  Is there something wrong?
> (To me, I think the energy with LDA+U should be always lower than
> that of LDA because of the lower symmetry. Am I right?)

Be very careful with interpreting total energies using LDA+U. Because 
of the non-variational character of this method, the total energy does 
not have a meaning as rigourous as in LDA or GGA. I don't think you 
can compare LDA+U with LDA energies, even two LDA+U energies with the 
same scheme are not necessarily comparible.

Conclusion: most likely, nothing is wrong with your case.

Stefaan