How to get the electron relaxation time

[prasad85sl]

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

[carla.verdi]

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

[prasad85sl]

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

[carla.verdi]

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