[Pw_forum] Another question regarding

[Youssef Aharbil]

Dear QE community and Dear Dr Matteo,

I have succedded to calculte the U parameters for some compounds including
double perovskite.

I've found for Ba2MgWO6 :

U for W=2.65 ev and U for O =14ev

Now I've apply this values to get the energy band gap and I found it 5ev
while the experimental one is 3.5ev, I think it's a strange result about
the overestimating the band gap while it's known that DFT underestimate it.

I Think that the root cause of that issue is the Hubbard of U of oxygen
which is double counted because O is only bonded to W with 50% ratio. I've
apply U for O = 7 and i get best result (Eg=3.2ev).

What do think about my logic


-- 

والله ولي التوفيق
يوسف أحربيل
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