Dear EPW users,

I read the paper EPW: Electronphonon coupling, transport and superconducting properties using maximally localized Wannier functions which is published on CPC. I found in (8) and (9), you do not include the efficiency factor, which is defined as following

\eta=1-cos\theta_{k,k+q}=1-\frac{v_{k}\cdot v_{k+q}}{v_k^2}

I checked the EPW code in version QE. 6.3 and I found for phonon linewidth, the efficiency factor is added and we can extract the phonon linewidth through the parameter gamma_tr. However, there is no efficiency factor for the electron linewidth calculation. Is this reasonable?

I also checked other papers and I find other papers (PRB 94?155105 (2016) PRB 57? 11276 (1998)) considered the efficiency factor.

Could you give some comments about this issue?

Thank you in advance!

--

Rgds,

Shouhang

## Efficiency factor in electron linewidth calculation

**Moderator:** stiwari