[DFTB-Plus-User] R: Phonon dispersion using single k-point hessian calculations.

Alessandro Pecchia alessandro.pecchia at cnr.it
Tue Nov 5 13:14:31 CET 2019


Dear Ansh,

in a forthcoming release of dftb+ there will be a phonon tool that I developed. 
It can calculate dispersions and coherent phonon transmission starting from the Hessian. 
For the moment you can try phonopy to get the dispersion. 

Regards,

Alex

-----Messaggio originale-----
Da: DFTB-Plus-User [mailto:dftb-plus-user-bounces at mailman.zfn.uni-bremen.de] Per conto di Benjamin Hourahine
Inviato: martedì 5 novembre 2019 11:46
A: dftb-plus-user at mailman.zfn.uni-bremen.de
Oggetto: Re: [DFTB-Plus-User] Phonon dispersion using single k-point hessian calculations.

Hello Ansh,

the k-points refer to the electronic structure only, not the phonon band structure (often the momenta there is labeled with q).

You can use phonopy to calculate dispersions, see

https://dftbplus-recipes.readthedocs.io/en/latest/properties/phonopy.html

for a worked example.

Regards

Ben

On 05/11/2019 07:36, Anshu Gaur wrote:
> Dear All,
>
> I am wondering if it is possible to calculate phonon dispersion for a 
> periodic structure by calculating hessian matrix (and corresponding 
> frequencies using 'modes') at various k-points (single k-point at a 
> time)? If we use "supercellFolding" to define k-points for the 
> calculation of hessian matrix, is this a k-point average hessian 
> matrix or just one point (k=0) hessian matrix?
>
> Regards,
>
> Anshu
>
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