EPW Forum

Dear EPW developers and users

I wanted to calculate the electron relaxation time of a metallic compound and I got to know EPW code can do this. I followed the examples to know how to run this code. Then I winterized my structure and could get a good band structure. Also I got the electron linewith.

But I am now bit confused how to proceed now to get the relaxation time as i didn't see any clear explanation on this. Can someone give me clear idea how to calculate the electron relaxation time after running epw.in and epw2.in?

Thank you
Prasad

Hi Prasad,
After you calculate the imaginary part of the e-ph self-energy, you can obtain the relaxation time using the standard definition hbar/(2ImSigma).
Best,
Carla

Dear Prof. Carla

Thank you very much for your prompt reply.

Do I have to refer "linewidth.elself' file to get Im(sigma)? For my case, I have wannierized 11 bands (both from conduction bands and valance bands) and hence getting information for 11 bands in linewidth.elself. So How do i decide which band I should consider?

I have another question;
Even if i select a band, since for my case there are 201 points (k-points) given, I have 201 Im(sigma) values for that band only. So do I have to take the average of all those relaxation times or do I need to consider only at gamma point or please advice me the correct way?


Thank you in advance

Prasad

Dear Prasad,

Yes you have to refer to the file "linewidth.elself". For which band to consider, it depends on the energy region you are interested in - e.g. you can try to plot everything and zoom in the region you are interested. Also for the k-points, it depends on what you are interested in specifically.
If you haven't done so already, reproducing some of the tutorials will help you getting familiar with extracting the linewidths.

Best
Carla