EPW Forum

Hello developers,
I am new to epw. I have followed the tutorial for direct evaluation of electron-phonon matrix elements along the
selected high-symmetry lines using density-functional perturbation theory with the input files in ephline folder. But it is not showing properly anything. I was running ph.x within PHonon/PH but it is not working , in the final ephline.out file |g| is not written for mnk. I have attached the input and output files. Also, without smearing it shows error like electron-phonon is implemented for metals only so i add a smearing in scf.in file. I have tried with both QE v 6.7 and 6.2.2. Both are not working. Can you please check and inform me where i did the mistake.

I have not found anything within the output file like this ibnd jbnd imode eig_i (eV) eig_j (eV) omega_nu (meV) |g| (meV)
...
4 4 6 9.359503 9.359503 95.957023 117.626599
also grep '4 4 6' sic.epw.out | awk {print $7} > matel.dat does now show any data in matel.dat

Thanking you
Sourav Rudra
PhD student
JNCASR Jakkur Bengaluru India

Dear Sourav Rudra:

For this tutorial, you should NOT use ph.x in the directory of PHonon/PH, but use my modified version in the directory of test-suite/not_epw_comp after building it.

For details, please see the exercise 2 of the document at https://drive.google.com/file/d/12wxuv5 ... sp=sharing with QE v7.1 at https://gitlab.com/QEF/q-e/-/releases/qe-7.1 .

Sincerely,

H. Lee

Thank you for the reply. I have installed QE_V7.1 in my system by ./configure and make all but I could not find the modified ph.x in the directory q-e-qe-7.1/test-suite/not_epw_comp after compiling QE 7.1. Can you suggests me how can i get ph.x executable in q-e-qe-7.1/test-suite/not_epw_comp?

Thanks with regards
Sourav Rudra
PhD student
JNCASR Jakkur Bengaluru India

Dear Sourav Rudra:

This code is not automatically built by issuing "make all" .

So, you need to compile the code separately.
Please issue "make" under the directory of q-e-qe-7.1/test-suite/not_epw_comp after building pw.x and ph.x .

Sincerely,

H. Lee

Thanks you for your help. Now i am able to calculate g matrix using modified ph.x executable
Thanks with regards
Sourav Rudra
PhD student
JNCASR Bengaluru India

Respected H. Lee,
I have tried to use modified ph.x for spin-orbit non-collinear case but is is showing an error like this:
[b]Error in routine phq_readin (1):
el-ph coefficient calculation disabled in noncolinear/spinorbit case[/b]
How can i calculate el-ph matrix elements for spin-orbit case?
Please help regarding this.
Thanks with regards
Sourav Rudra
CPMU,JNCASR