[QE-users] Enquiry about electron-phonon calculation

[Nicola Marzari]

On 06/12/2021 08:59, Lorenzo Paulatto wrote:
> Yet it is possible. You need a very goo representation of the Fermi 
> surface in order to identify the possible el-ph processes, but such a 
> fine grid is not required to have good phonons.
> 
> Also note that there are at least two QE packages to do el-ph 
> calculation with Wannier interpolation : epik by M Calandra and EPW by F 
> Giustino
> 

Thanks Lorenzo - maybe just for completeness I should add the other two 
I know of (to 4 altogether - an embarassment of riches...):

Perturbo: https://perturbo-code.github.io/
Phoebe: https://arxiv.org/abs/2111.14999

Also, I do not think epik is available open-source somewhere, correct?

				nicola


> regards
> 
> --
> Lorenzo Paulatto - Paris
> On Dec 6 2021, at 3:27 am, Elio Physics <Elio-Physics at live.com> wrote:
> 
>     Dear all,
> 
>     As is well known in electron-phonon calculations, one has to do a
>     self consistent (scf) calculation over a dense electronic grid
>     followed by an scf calculation on a coarse grid.
>     The electron phonon calculation is usually performed after
>     calculation the vibrational frequencies for each point.
> 
>     My question is : If we increase the dense grid, Is it possible (Is
>     there a way in QE) to compute the el-ph coefficients without
>     recomputing the dynamical files (vibrational frequencies), which
>     actually depend on the coarse grid.  This would save a lot of time.
> 
>     Thanks in advance
> 
>     Ellie Moujaes
>     Federal Universil of Rondonia
>     Brazil
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, SNSF
Head, Laboratory for Materials Simulations, Paul Scherrer Institut
Contact info and websites at http://theossrv1.epfl.ch/Main/Contact