[Pw_forum] Phonon group velocity in different directions

[Stefano Baroni]

I do not understand the question. Or, at least, it seems to me that you have already given the answer. What's wrong with calculating the slope numerically? Stefano
 
On Jun 16, 2012, at 1:45 AM, Payam Norouzzadeh wrote:

> Dear QE users
> 
> I have a question about calculation of phonon group velocity:
> I know that it is the slope of phonon dispersion curves (w versus k) but  how can I calculate phonon group velocity in different directions of a crystal like in direction of x,y or z?
> Is it possible in QE to calculate them seperately and have vx,vy,vz for phonons?
> I appreciate any useful comment.
> 
> Best regards,Payam Norouzzadeh 
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center - Trieste
http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

La morale est une logique de l'action comme la logique est une morale de la pensée - Jean Piaget

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