EPW Forum

Dear Shubham, The .dvscf file contains part of the dV^KS/dU. One then have to add the Ewald terms and then take the sandwich with the wavefunctions. The whole term <u|dV/du|u> is contained in the .epb files. Note that in EPW we have it for <k+q|dV/du|k> so you will need to look at q=\Gamma only for ...

Hello,

I confirm that this is the issue. Your Wannierization is of bad quality and different in the two outputs because you use random Wannier functions.

The use of 'random' is strongly discouraged as it often produce bad results.

Best wishes,
Samuel

Hello,

We like to decouple things so that everything is clear.
In principle it is indeed not needed and the following should work
scf.in
ph.in
pp.py
nscf.in
epw.in

Best wishes,
Samuel

Hello, This means that there is an incompatibility between your phonon calculation (dvscf files) and the current EPW calculations. Note that the new version of EPW v5.8 (to be released very soon) will include support for 2D materials. You can already download the development version here if you are ...

Dear Nasrin, Indeed EPW does not support magnetic calculations. You can try running EPW without magnetism as an approximation. You can read external eigenvalues (.eig files), such as from calculations made with HSE. It will not impact the electron-phonon matrix element directly but will have an ...

Dear Pravin Karna,

As indicated in the tutorial, you need to use QE 7.2.

Best wishes,
Samuel

Hello Muhammad,

The code will work and produce results.

However if the band is too flat, the BTE theory is indeed not expected to hold.
In that case you will likely create polaron etc.

I would therefore be very cautious with very flat band materials.

Best wishes,
Samuel

Dear Muhammad Aminul Haque, Welcome on the EPW forum ! First, it is recommanded to use the same multiplicative factor between the coarse k-point and q-point grid. Therefore if you have a 4x4x2 q-point grid, you can have a 8x8x4 grid or 12x12x6 k-point grids. The pw.x code in calculation mode "nscf ...

Hello,

It seems that the inputs could be fine.
Could you provide the full backtrace of the problem ?

Thanks,
Samuel

Hello,

It is indeed the Phonon linewidth, expressed in meV.
The factor to go from energy, expressed in Ry to a rate in 1/ps is 20670.6944033.

Best wishes,
Samuel