[Pw_forum] how to judge movement of HOMO and LUMO

[Nicola Marzari]

If you have a thin film none of the discussion on the forum applies
to you. The disucssion was only for bulk materials in 3d.

So, for your thin film, at each level of strain you can calculate
simultanneously the band structure, and where the vacuum level is,
so you are in good shape.

				nicola


On 05/06/2014 08:53, Rajdeep Banerjee wrote:
> Dear Prof. Marzari,
>                             thank you very much for all your suggestions
> and concerns. I'm really overwhelmed !
>                             I've looked at work function calculation
> (thanks to the links you provided). Now, I have a monolayer of
> crystalline non-polar semiconductor material and I can calculate the
> planar and macroscopic averages for unstrained and strained cases. But
> I'm still a little bit confused about fixing the reference. Should I
> take macroscopic average of Hartree potential at vacuum as the reference ?
>
> I've thought about the following steps (in light of your previous
> explanation):
>
> 1. Do a bulk calculation and find out the macroscopic average
> 2. Do the strained monolayer and see where the macroscopic average sits
> with respect to vacuum level.
>     But then I don't understand why do we need a bulk calculation if I
> can get the vacuum level (in sigle-layer) and can align it for all
> strain cases and refer the HOMO-LUMO directly to that !
>
>                                I know I have a lot of doubts and I truly
> appreciate your patience and all your helpful suggestions.
>
> Thanks,
> Rajdeep Banerjee
> JNCASR
> Bangalore, India
>
>
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-- 

----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL