Analysing elph matrix elements

[sitangshu]

Dear Yambo guys,

There are some of my queries regarding elph data:

1. Is

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Sc|E [eV] 

appearing in elph o-qp-0K.qp file is self energy including elph corrections? If so, how can I get electron-acoustic & electron-optical phonon self energies?

2. Is

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Re(G) [eVm1]

appearing in elph o-sf-0K.G_Sc_band_* file gives the Re[spectral function]? The header seems to be Re[Green]

3. I have now the SAVE folder where ndb.elph.gkkp* elph matrix element files are there together with the ndb.PH_Double_Grid file. How can I get information about the electron-acoustic and electron-optical phonon deformation potentials?


Regards,
Sitangshu

[claudio]

Dear Sitangshu

answers to your questions:
1) yes it is the electron-phonon self-energy

if you want self-energy only for the acustic or for the optical phonons,
you just select them in the input and repeat the calculation.
For example for the autistic you can set:

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% ElPhModes
  1 |  3 |                           # [ELPH] Phonon modes included
%

and for the optical

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% ElPhModes
  4 |  xx |                           # [ELPH] Phonon modes included
%

where xx is your last phonon mode.

2) I have to check

3) other people will reply to this question

[palful]

Hi Sitangshu,

2) This should indeed be the real part of the quasiparticle electron Green's function after electron-phonon effects are included. Its imaginary part (Im[G]) is the spectral function instead. But let's wait for Claudio to confirm. Getting the frequency-dependent, complex Green's function or just the linearised quasiparticle solution (i.e., only band shifts and broadenings) depends on the solver option in the input.

3) You could visualize the k-space or q-space maps of the electron-phonon interaction potential (the 'g' matrix elements) using yambopy. In particular you can check this part of the yambopy tutorial. The relevant scripts are in the yambopy repository at tutorial/databases_yambopy.

Cheers,
Fulvio

[sitangshu]

Hello Professor Claudio and Fulvio,

Many thanks for your answers.
I am trying to compute the mode dependent elph scattering rates, which are proportional to the -Im[elph self-energies]. If I know this somehow, then I can also find out other transport coefficients like mobility etc. The code seems to write only the Real part

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Sc|E [eV] 

. Is there anyway to get also the Im[elph self-energies]?

Regards
Sitangshu

[sitangshu]

Apparently, I could not get around of this super bug in the elph spectral function output. This E-152 seems to be always coming. Is this a problem with this version?

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#Version 5.1.0 Revision 21422 Hash (prev commit) fde6e2a07           
#                        Branch is                                    
#               MPI+SLEPC+HDF5_MPI_IO Build                           
#                http://www.yambo-code.org   
#
#
# Spectral function at this point integrates to:  0.4082163E-152
#
#
#    Energy [eV]        Re(G) [eVm1]       Im(G) [eVm1]       Re(S_tot) [eV]     Im(S_c) [eV]
#
       -1.890873          -0.341685           0.1670E-155       -0.073324           0.1430E-154
       -1.878849          -0.343094           0.1684E-155       -0.073324           0.1430E-154

I have attached the report file and the sf output also. The ZPR gap seems to be reasonable.
I am although aware of Professor Attacallite's response:

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Dear Sitangshu

I tried to reproduce your error with the last version of the GPL

https://github.com/yambo-code

but I did not get any error.
Please try again with the last version, and in any case use the same version
of Yambo for the BSE and the interpolation

best
Claudio

An advice (perhaps the Yambo version with a revision number and branch number) will be be greatly admired.

Regards
Sitangshu

[sitangshu]

File is attached.
Regards

[sitangshu]

Any update?

Regards,
Sitangshu