[Pw_forum] Electron affinity calculation

[Alexander Shaposhnikov]

I have tried several slab models and the first conduction band
is still meaningless, i.e. much higher than it should be in real crystall.
I have not tried to optimize the structures though.

I guess, i have to
1. Optimize the structure.
2. Remove some electrons from the system, hoping to create surface charge. 

Am i right here?

Best Regards,
Alexander Shaposhnikov



On Saturday 27 January 2007 14:22, Alexander Shaposhnikov wrote:
> Hello Dr. Baroni,
>
> Thank you, i was thinking about  surface myself,
> good to know i was in the right direction!
> I will try to create slab surface model.
>
> Best Regards,
> Alexander Shaposhnkov
>
> On Saturday 27 January 2007 13:54, Stefano Baroni wrote:
> > On Jan 27, 2007, at 8:39 AM, Alexander Shaposhnikov wrote:
> > > My question is, what is the established approach for the
> > > calculations of
> > > electron affinity for the plane wave band dft calculations?
> >
> > I believe, you should first ask (and answer) the preliminary
> > question: what makes " ... the first conduction band ...
> > meaningful ..?.. " The answer does not depend on the theoretical
> > approach (DFT), nor on the basis set (plane waves), but on nature:
> > the surface. So, in order to calculate electron affinities in an
> > extended system you have to simulate "the place the added electron
> > comes from", i.e. the vacuum, and the interface between that place
> > and the solid, i.e. a surface.
> >
> > Hope this clarifies a bit.
> >
> > Stefano
> >
> > ---
> > Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -
> > Trieste
> > [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
> >
> > Please, if possible, don't  send me MS Word or PowerPoint attachments
> > Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html
>
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