How many Wannier bands (nbndsub) we should consider for Eliasberg Formalism?

[simba2828]

Dear EPW experts,

I am very new to the EPW and Migdal-Eliasberg formalism. About the EPW calculation, I want to know that for how many bands we should do the Wannier interpolation to get the good estimate of Tc and Superconducting (SC) gap. Does it matter if I fit all the DFT bands in one case and few bands about the Fermi level in a second case? Will that affect my Tc and SC gap?

Thank you
Shubham,
IIT Kharagpur

[hpaudya1]

Hi Shubham,

As long as you have all bands inside the Fermi window (ie. from -fsthick to +fsthick) and the Wannier functions are well decayed (please plot and compare your Hamiltonian and el-ph decay) it should not affect the Tc and SC gap.

Happy EPWing,
Hari

[simba2828]

Thank you Hari for your kind suggestion.

Here I am attaching the Hamiltonian and el-ph decay. Could you please tell me is it fine? This looks noisy to me.

Shubham

[hpaudya1]

Hi Shubham,

You can go through the first paper of the EPW code; https://www.sciencedirect.com/science/a ... via%3Dihub, where you can see the decay plots in Fig. 2.

Happy EPWing,
Hari