[Pw_forum] Electron-Phonon couplings for insulators

[Lorenzo Paulatto]

On 09/06/2015 18:05, Carlo Motta wrote:
> Dear all,
>
> is it possible to compute the electron-phonon couplings for insulating systems?
> I tried and got this error:
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>       Error in routine phq_readin (1):
>       Electron-phonon only for metals
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
> Thanks in advance,
>
Yes, you can put a small smearing and fake your insulator as a metal, 
but does it make sense?

You would get zero, unless you have some phonons with energy higher than 
the electronic gap (1eV=8065cmm1), and a non-zero Bose-Einstein 
occupation at a reasonable temperature (1cmm1=1.4Kelvin*kB).

HTH

-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
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