[Pw_forum] Confusion about silicon phonon dispersion along K-X path
nicola.marzari at epfl.ch
Sat Jul 8 11:32:00 CEST 2017
There are two gamma to X paths - the "short" one [a,0,0], where
a goes from 0 to 1, and the "long" one [a,a,0], also with a going
from 0 to 1.
These are called the delta path and the sigma path:
For this lattice the end points are equivalent ([1,0,0] and [1,1,0])
but the sigma path goes though K [3/4,3/4,0]. Try to visualize in the
wikipedia page where [1,1,0] is, and why it is equivalent to [1,0,0].
Also, you can use SeeK-path
to automatically created for any structure the k-point path that
follows the correct crystallographic conventions.
On 08/07/2017 07:27, balabi wrote:
> Dear developers,
> I am calculating silicon phonon dispersion, however, I got confused
> about the dispersion along K-X.
> I found there are apparently different results on the web. Some are
> the same with my calculation, most are not.
> My result along k-path "Γ - K - X - Γ - L" is here:
> The only result that is the same with me is on QuantumWise page :
> However, most of the results that I googled is quite different
> along K-X, for example
> or paper
> DOI: 10.1103/PhysRevB.87.165201 in which the author claimed
> they calculate the phonon by QE
> I notice that the length of K-X is not the same in two different
> Besides the same problem exists for similar structure like AlAs etc.
> But I don't know what is going wrong here? Which is the right
> result? Thank you for helping.
> best regards
> Pw_forum mailing list
> Pw_forum at pwscf.org
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
More information about the users