Electron-phonon calculation

[yanghao]

Dear developers,

I am trying to follow the Si el-ph calculation tutorial in yambo-py. I managed to generate ndb.elph_gkkp* files but failed to start the calculation of el-ph correction.
The problem is that I can not generate proper input file for yambo_ph. If I follow the command ''yambo_ph -g n -c p' in "elph_qp_si.py" file from the yambo-py tutorial, I got an input file like this,

Code: Select all

gw0                          # [R GW] GoWo Quasiparticle energy levels
rim_cut                      # [R RIM CUT] Coulomb interaction
HF_and_locXC                 # [R XX] Hartree-Fock Self-energy and Vxc
RandQpts=0                   # [RIM] Number of random q-points in the BZ
RandGvec=0             RL    # [RIM] Coulomb interaction RS components
CUTGeo= "none"               # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere
% CUTBox
 0.00     | 0.00     | 0.00     |        # [CUT] [au] Box sides
%
CUTRadius= 0.000000          # [CUT] [au] Sphere/Cylinder radius
CUTCylLen= 0.000000          # [CUT] [au] Cylinder length
EXXRLvcs=  5985        RL    # [XX] Exchange RL components
%QPkrange                    # [GW] QP generalized Kpoint/Band indices
  1| 13|  1| 20|
%
%QPerange                    # [GW] QP generalized Kpoint/Energy indices
  1| 13| 0.0|-1.0|
%

, which does not seem to contain the information for el-ph calculations. I checked the help message of yambo_ph and yambo.h file and found that the argument might be '-s p' for el-phonon calculation. However, the command yambo_ph -g n -s p gives

Code: Select all

 gw0                          # [R GW] GoWo Quasiparticle energy levels
HF_and_locXC                 # [R XX] Hartree-Fock Self-energy and Vxc
EXXRLvcs=  5985        RL    # [XX] Exchange RL components
%QPkrange                    # [GW] QP generalized Kpoint/Band indices
  1| 13|  1| 20|
%
%QPerange                    # [GW] QP generalized Kpoint/Energy indices
  1| 13| 0.0|-1.0|
%

, which still does not seem to be correct for el-ph calculation.

I also tried to perform the calculation with the database and input file provided from the tutorial section in the Yambo main page but the calculation finished with a warning message "[WARNING]Both e-p and e-e correlation switched off". Please find the input and output file in the attachment.

I am wondering if this is because I did not compile it correctly and what is the correct procedure to do the electron-phonon calculation. Thank you in advance!

p.s I use YAMBO 3.4.2 released together with Quantum Espresso 5.4.0

[amolina]

Dear Yang-hao,

for some reason you are not activating the run-level el_ph_corr. If you put in yambo.in the flag el_ph_corr it should work and finish the calculation. I have tried with the yambo gpl version 4.1.0 and it works as expected. You may compile the latest gpl version and you should be able to run the example without troubles. From now on, we will say in the yambopy website which yambo versions you should use to run the scripts!

Cheers,

Alejandro.

[yanghao]

Dear Alejandro,

Thank you for your quick reply and suggestion!
As you suggested, I switch to yambo 4.0.4 and everything works well now.

Sincerely,
Yang-hao