[Pw_forum] Should I scrap the nonanalytic part of DM in electroded thin films?

[Nicola Marzari]

Dear Serge,


I think I've found the perfect reference: vibrational
properties of a BN sheet deposited over different metals:
http://prola.aps.org/abstract/PRL/v79/i23/p4609_1

(and indeed different metals lead to a different properties,
with Ni having perfect screening, and LO/TO degeneracy).

				nicola



Serge Nakhmanson wrote:
> Stefano, Nicola,
> 
> Thank you for your comments -- this is some good food for thought!
> Making electrodes an explicit part of the calculation will
> surely be necessary in the case of thin-ish films, but it
> opens its own big can of worms (band alignment between components
> with DFT band gaps, etc; I bet you know the issues very well)
> I do not want to deal with in this particular project. For
> the case of thick-ish films with assumed perfect screening
> I could probably guesstimate things around Gamma by taking an
> "honest" bulk case as a reference and then playing with phonon
> postprocessing routines (easy, since no new time-consuming DM
> calculations are required).
> 
> But, I guess, the thought of how to add screening to this
> process in a more rigorous fashion is worth some additional
> thinking.
> 
> THX,
> 
> Serge
> 
---------------------------------------------------------------------
Prof Nicola Marzari   Department of Materials Science and Engineering
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