EPW Forum

Dear developers,
I ran the e-pl in the test suite for silicon. And I have several questions as following:
1). How do we set the 3 parameters?
nel = 0.01
epsiHEG = 12.0
meff = 0.25
2). the q point in the ph.in just contains only 1 1 1, and in epw.in, there are no fine grids. Is this just for testing? Do we still
need to set interpolated finegrids here?

Thanks!

Shudong

Dear Shudong,

nel is equivalent to tot_charge (in absolute value), that is, the added electrons in your unit cell. epsiHEG is the average \epsilon_\infty e.g. from your dfpt calculation. meff is the average band effective mass for your material.
The electron-plasmon coupling is implemented as in https://journals.aps.org/prb/abstract/1 ... .94.115208 and https://journals.aps.org/prb/abstract/1 ... .97.165113 using EPW to take advantage of the Wannier interpolation, but it doesn't need the interpolation of the e-ph matrix elements, hence why the ph.in only contains 1 q point.

Best
Carla