[Pw_forum] Phonons calculations at Gamma

[Nicola Marzari]

On 30/09/2014 18:49, Said Asma wrote:
> Dear Nicola,
> Thank you for your replay,
> yes I've done the math with two atoms, but I'll make an alloy that is
> why I did it with 16 atoms.
>
> Asma
>

It looks like the LA and one of the TA become degenerate at X
(if I got the right phonons - prb site is down); X folds
into Gamma in your supercell. I am not sure on what
are the different representations of the "small point group"
that you have at X, and how they are labeled, but the LA and
TA labels are only valid in the Gamma limit (I think).

			nicola



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