[Pw_forum] charged defect

[Giuseppe Mattioli]

Dear Ali

> >  I want to study O vacancy in TiO2 bulk

There's a lot of people studying such an issue...!
First, I suggest reading at least these papers:

Phys. Rev. B vol. 73, pag. 125205 (2006).
J. Chem. Phys. vol. 129, pag. 154113 (2008).
Phys. Rev. B vol. 76, pag. 045217 (2007).
Phys. Rev. B vol. 78, pag. 241201 (2008).

Then, you will be aware that you need very large supercells and some kind of 
beyond-LDA (LDA+U or hybrid xc functionals) approximation in order to achieve 
a good description of point defects in TiO2.

So, have a nice time...

Dear Paolo

> it's tricky, very tricky. May I suggest the following recent paper
> by Alex Zunger: Phys. Rev. B78, 235104 (2008)? it is a general
> paper on the problem of formation energies in charged defects.

It's more than tricky...
I'm starting in to think that TiO2 is not really a "regular" semiconductor. 
The paper by Zunger is of course an in-depth one, but native point defects in 
TiO2 seems to behave in a different way than, e.g., oxygen vacancies in ZnO 
(one of the topics of the Zunger's paper).
This is not the suitable place for long debates, but I hope that such a scrap 
of an information can be useful to somebody.

Cheers to everybody

Giuseppe

On Tuesday 21 April 2009 12:19:32 Paolo Giannozzi wrote:
> On Apr 11, 2009, at 13:26 , ali kazempoor wrote:
> >  I want to study O vacancy in TiO2 bulk
>
> it's tricky, very tricky. May I suggest the following recent paper
> by Alex Zunger: Phys. Rev. B78, 235104 (2008)? it is a general
> paper on the problem of formation energies in charged defects.
>
> Paolo
> ---
> Paolo Giannozzi, Democritos and University of Udine, Italy
>
>
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   Giuseppe Mattioli                            
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
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