How to plot lmabda w.r.t. omega

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AmirhTalebi
Posts: 11
Joined: Fri Jul 10, 2020 8:37 am
Affiliation: University of Luxembourg

How to plot lmabda w.r.t. omega

Post by AmirhTalebi »

Hell
I am using quantum espresso and am almost new in using ewp.x executable.
I have done the computations for Al element, however still I have no clue how to find the final values for the elph_coupling constant!
I think i have to plot it w.r.t omega. However, what is omeag?(as we have one other omega known as: \omega_log).
here one output for lambda.dat

# degauss lambda int alpha2F <log w> N(Ef)
0.005 0.292222 0.292222 392.155 1.339210
0.010 0.434755 0.434912 352.861 1.881761
....


Any kind of help of hint is welcome!

Thanks a lot
Amir

hlee
Posts: 415
Joined: Thu Aug 03, 2017 12:24 pm
Affiliation: The University of Texas at Austin

Re: How to plot lmabda w.r.t. omega

Post by hlee »

Dear Amir:
I have done the computations for Al element, however still I have no clue how to find the final values for the elph_coupling constant!
I think i have to plot it w.r.t omega. However, what is omeag?(as we have one other omega known as: \omega_log).
here one output for lambda.dat
I think that lambda.dat you are referring to was obtained from using phonon code, not EPW.
The electron-phonon coupling strength doesn't depend on omega while the isotropic Eliashberg
spectral function depends on omega through the Dirac delta function with the phonon frequency; See Eqns.(3) and (4) in https://www.quantum-espresso.org/Doc/ph_user_guide.pdf .

Added after my first post:
If you want the total e-ph coupling strength (the integrated value), you can find it in the output of EPW (I am not sure, but you need to set liso=.true. ).

Sincerely,

H. Lee

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