[Pw_forum] Fw: defect formation energy

[Sanda Botis]

I agree that is probably an effect of the supercell size. How big is the
supercell that you are using?

Cheers,
Sanda

On Fri, Sep 18, 2009 at 8:47 AM, Duy Le <ttduyle at gmail.com> wrote:

> if the defect concentration is too hight, when you do vc-relax the lattice
> parameter will be re-optimized. In reality, the defect concentration is
> about zero.
>
> On Fri, Sep 18, 2009 at 8:43 AM, xirainbow <nkxirainbow at gmail.com> wrote:
>
>> Dear:
>>
>> When you calculate without vc-relax, you deal with a point defect.
>> When you use vc-relax, you change the crystal parameters. That is to say,
>> you deal with a new kind of crystal, not a point defect.
>> It is just my own point of view ：）
>>
>>
>>
>>>
>>> Ali Kazempour
>>> Physics department, Isfahan University of Technology
>>> 84156 Isfahan, Iran. Tel-1: +98 311 391 3733
>>> Fax: +98 311 391 2376 Tel-2: +98 311 391 2375
>>>
>>> --- On *Fri, 9/18/09, ali kazempour <kazempoor2000 at yahoo.com>* wrote:
>>>
>>>
>>> From: ali kazempour <kazempoor2000 at yahoo.com>
>>> Subject: defect formation energy
>>> To: forum at democritos.it
>>> Date: Friday, September 18, 2009, 5:31 AM
>>>
>>>
>>> Hi
>>> for study of point defect ,  i do relax calculation and obtain positive
>>> defect formation energy while by vc-relax i gain negative. ?
>>> what is the difference between positive and negative formation energy?
>>> waht is the physical reasons?
>>> thanks a lot
>>> Ali Kazempour
>>> Physics department, Isfahan University of Technology
>>> 84156 Isfahan, Iran. Tel-1: +98 311 391 3733
>>> Fax: +98 311 391 2376 Tel-2: +98 311 391 2375
>>>
>>>
>>
>>
>> --
>> ____________________________________
>> Hui Wang
>> School of physics, Nankai University, Tianjin, China
>>
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>>
>
>
> --
> --------------------------------------------------
> Duy Le
> PhD Student
> Department of Physics
> University of Central Florida.
>
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