[Pw_forum] U calculation in GGA+U

[Peng Chen]

Dear All,

In the calculations of U, I remember that I got some advice from the forum
that  the equivalence of the ions is determined by  space group symmetry
not site symmetry.   E.g  AB2O3, B ions has 2 different site symmetries
(B(1) B(2)).  We should only run the calculation on perturbing B ions. But
from  Dr. Matteo Cococcioni's paper (PRB 71, 035105 (2005)),  both Fe1 and
Fe2 of fayalite are perturbed and have different U values. I think Fe1 and
Fe2 are  different in site symmetry. So I am just curious which  is the
best way to do the same kind of calculations.

-- 
  Best Regards.
        Peng
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20121202/23b58505/attachment.html>