Phonon interpolation error around Gamma point

[tessw]

Hi all,

I have some trouble with EPW in combination with the phonon calculation. In the attached image, you can see the phonon dispersion as calculated by ph.x (4 4 4 grid) in yellow and the EPW interpolation in red. Most of the dispersion is fine, but around Gamma, some weird things happen, which look like interpolation errors to me. I tried to find similar reports in the forum and elsewhere, but could not. Is there any flag I am missing, am I doing the linewidth calculation wrong or has someone else already had the same troubles? The structure is fully relaxed and I am using optimized norm-conserving pseudopotentials.

Thank you very much and best regards,
Tobias

[sponce]

Dear Tobias,

Maybe you can try using the crystal asr with the "lifc" and "asr" input variable in EPW.
Note that in that case, you need to first run "q2r" to create the IFC in real space and then copy it inside the "save" folder.

Best wishes,
Samuel