how to set fsthick and.....

General discussion around the EPW software

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1504463450
Posts: 17
Joined: Thu Sep 29, 2022 12:51 pm
Affiliation: Physics-superconduct

how to set fsthick and.....

Post by 1504463450 »

Dear friends
Is there any skill and basis for setting parameters "fsthick", wscut" and" muc" in EPW calculation?
Yours sincerely
Shi

hpaudya1
Posts: 190
Joined: Tue Mar 21, 2017 7:11 pm
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Re: how to set fsthick and.....

Post by hpaudya1 »

Hi Shi,

You need to get your results converged with respect to fsthick and wscut. Typically, we use;

fsthick = 4 times the maximum phonon frequency (and also please set your degaussw to 1/4 of fsthick)
wscut = 10 times the maximum phonon frequency
and
muc = 0.1 to 0.2 (you can compare your Tc with expt. to estimate muc)

I hope it helps.

Happy EPWing,
Hari

Kunsa
Posts: 5
Joined: Sat Nov 26, 2022 6:24 pm
Affiliation: Ethiopia/phd student

Re: how to set fsthick and.....

Post by Kunsa »

How to get maximum phonon frequecy for wscut setting? when I see ph.out file it is too big 10HZ. Any one help me?

hpaudya1
Posts: 190
Joined: Tue Mar 21, 2017 7:11 pm
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Re: how to set fsthick and.....

Post by hpaudya1 »

Hi Kunsa,

By default, Quantum ESPRESSO prints phonon frequency in THz and cm-1 units. Look at them, and find what is the maximum (no need of exact value). For e.g. in MgB2, I get ~800 cm-1 maximum phonon frequency, which is ~0.099184 eV and choose wscut = 1 eV (which is close to 10 times max. ph freq.).

I hope it helps.

Happy EPWing,
Hari

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