[QE-developers] graphene phonon band obtained by QE 6.6

[A]

Dear QE developers,


Recently, I calculate the phonon band of graphene by QE6.6. If the q point is 6x6x2, the result if fine. However, if the q point is 6x6x1,  all the frequencies become their negative values (see the matdyn.freq.gp). 


So, what is the problem?  How to solve this question or how to improve the input files for the case of 6x6x1 calculations?


Thank you so much.  I look forward to your reply.


Best ragards,


J.B. Liao
Henan Normal University
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