cumulative electron-phonon coupling strength as a function of frequency

[karimskii]

Dear all,

I am a new user of EPW. While trying to reproduce some of the results available in the tutorial, I encountered a problem that I cannot overcome by myself. Indeed, in the example of MgB2, my calculation shows that the file MgB2.a2f contains only the Eliashberg spectral function. It doesn't contain the cumulative electron-phonon coupling strength while in the tutorial it is mentioned that this file does contain both.

Any help is welcome.

Best regards --- Karim

[hlee]

Dear Karim:

Which version of EPW are you using?

Using the current version of EPW v5.3.1 included in QE v6.7 (https://gitlab.com/QEF/q-e/-/releases), you can find the cumulative values in *.a2f file as you can see below

(the header of MgB2.a2f file)

w[meV] a2f and integrated 2*a2f/w for 10 smearing values

I would suggest you always to use the recent version of EPW since it contains several bug fixes and improvements.

Sincerely,

H. Lee

[karimskii]

Dear Dr. H. Lee,

Thank you very much for the feedback. I'm using the latest version (EPW v5.3.1 ). Sorry to bother you with my questions . Is there a command that i have to add to input file "epw.in" of MgB2 example to allow "epw code" to calculate it.

Best regards,

Karim

[hlee]

Dear Karim:

Could you try to run the example for MgB2 in q-e/EPW/examples/mgb2 and confirm that you still can't obtain the integrated values?

In most cases for superconductivity calculations, for example, laniso is true, prefix.a2f file is generated as you can see in the file of eliashberg.f90 and the subroutine of evaluate_a2f_lambda in supercond.f90 in the EPW source directory, q-e/EPW/src .

Sincerely,

H. Lee

[karimskii]

Dear Dr. Lee,

I solved the problem with your precious help. Thank you very much.

Best regards,

Karim