[Pw_forum] metal insulator interface simulation!

[Nicola Marzari]

Mohamed.Majdoub at mail.uh.edu wrote:

> 1- how can I combine a metal and insulator in the same calculation and 
> input file?
> I know that for metal we need to specify how metallicity is treated 
> (occupations='smearing' for example). If I specify it in the same input 
> file will it be fine for the insulator.

Yes, treat everything as a metal. Even if you were to treat a "pure"
insulator as a metal, you'd discover that, provided the gap is larger (a
few times) than the smearing temperature, the unoccupied bands are
empty, and your calculations reproduce the same results you'd
obtain by treating the insulator as an insulator.

> 2- how can I extract local potential?
> In the manual pp.x (post processing) we have
> 
> plot_num    selects what is saved in filplot:
> 
>   !                1=total potential V_bare+V_H + V_xc
>   !                2=local ionic potential
>   !               11=the V_bare + V_H potential
>   !               12=the electric field potential
> 
> which of these quantity will correspond to the total local potential 
> (ionic + Hartree)?
> exact definition for Hartree and exchange correlation contributions?
> 
> Please advice if you have any useful information that can help me out.
> Your suggestions and help are welcomed!

Have a careful look at Caspar Fall PhD thesis, from www.epfl.ch .
Look at the recent papers by Stengel and Spaldin (Nature, and PRB).

Try and see how 1, 2, and 11 look like.

			nicola


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