Electron-Phonon effects

[kazemoor]

Dear yambo developers

In order to compute the electron-phonon effect yambo needs to use some databases obtained with espresso . Would you please explain which version of espresso
needs to be compile with extra patches like in tutorial and how we can get the el-ph databases ndb.elph_gkkp_fragment?

thanks a lot
Ali Kazempour, Pnu University, Tehran, Iran

[andrea marini]

Dear Ali, I am working on the problem. The currrent interface to PW is out-of-date and quite elaborated. So I am coding a new interface to be embodied in the QE distribution. I am, however, heavily overloaded and this may take a while. Sorry for this!

Andrea

[Daniele Varsano]

Dea Ali,
We have opened a subforum concerning electron-phonon calculation were you can post there problem you are facing and where we will be posting news about the ongoing development of the interfaces with Quantum Espresso as weil as technical and methodological informations about how to use the code.

Best,

Daniele

[Khaled]

Dear developers,

I heard everything related to elctron-phonon effects are fully working and the pw-yambo interface has been released with the latest QE source. The tutorial in yambo site doesn't provide with the input files for the DFT and Phonon calculations stage. Please can you provide or at least guide me with these files to be able to understand and go through p2y interface without making any errors. Thank you in advance.

Best regards,

[amolina]

Dear Khaled,

we have a brief tutorial, which uses yambopy (http://yambopy.readthedocs.io/en/latest ... raction-si). It contains the basics to run the latest version of QE+Yambo and it will be enlarged soon. You can already start from there and combine with the existing documentation about el-ph hosted in the yambo website.

Kind regards,

Alejandro.

[Daniele Varsano]

Dear Khaled and Alejandro,
there is now a subfourm dedicated to el-ph interaction.
In my opinion if you post there question and answers related to the topics it will be ore visible also for the other users.

Many thanks,

Daniele

[martinspenke]

Dear Alejandro,

Sorry for posting here, since there is no "newtopic" button in the Electron-Phonon effects subforum to be able to post there.

1) I obtain this notification :

Code: Select all

 PW(ELPH) databases ...[PHONON] ...found 8 NOT Q-grid compatible

Is it fine to have a non Q-grid compatible grid ?

2) Is yambo capable of calculating phonon-phonon interaction in the GPL version ?


Bests
Martin

[amolina]

Dear Martin,

I guess is OK to get the message of NOT Q-grid compatible when you are calculating electron-phonon corrections. If you are using a random q-grid this is normal.

Phonon-phonon interaction is not yet available.

Cheers,

Alejandro.

[martinspenke]

Dear Alejandro,

When i use the secant method i end up with a segmentation error while running G0W0 calculation.
I obtain no error from other solvers. However, when i use the newton solver, it only performs electron-phonon self energy calculation and NO G0W0 calculation
(for electron electron part) as in the case of secant method using the same input file. Is this normal ?

Code: Select all

 <02s> [RL indx] Q BZ pts are /= from X grid BS pts. Gamma point only.
 <02s> [04] External corrections
 <03s> [05] Dyson equation: Newton solver
 <07s> [06] Correlation: Phonon-mediated Self-energy
 <08s> El-Ph Sc [coeff] |########################################| [100%] --(E) --(X)
 <08s> El-Ph Sc   [sum] |########################################| [100%] --(E) --(X)
 <12s> [07] QP properties and I/O
 <13s> [08] Game Over & Game summary

This is my input file :

Code: Select all

gw0                          # [R GW] GoWo Quasiparticle energy levels
el_ph_corr                   # [R] Electron-Phonon Correlation
StdoHash=  40                # [IO] Live-timing Hashes
Nelectro= 8.000000           # Electrons number
ElecTemp= 0.000000     eV    # Electronic Temperature
BoseTemp=-1.000000     eV    # Bosonic Temperature
OccTresh=0.1000E-4           # Occupation treshold (metallic bands)
NLogCPUs=0                   # [PARALLEL] Live-timing CPU`s (0 for all)
DBsIOoff= "none"             # [IO] Space-separated list of DB with NO I/O. DB=(DIP,X,HF,COLLs,J,GF,CARRIERs,W,SC,BS,ALL)
DBsFRAGpm= "none"            # [IO] Space-separated list of +DB to be FRAG and -DB NOT to be FRAG. DB=(DIP,X,W,HF,COLLS,K,BS,QINDX,
SE_CPU= ""                   # [PARALLEL] CPUs for each role
SE_ROLEs= ""                 # [PARALLEL] CPUs roles (q,qp,b)
DysSolver= "n"               # [GW] Dyson Equation solver ("n","s","g")
GphBRnge=  50                # [ELPH] G[W] bands range
FANdEtresh=0.1000E-5   eV    # [ELPH] Energy treshold for Fan denominator
DWdEtresh=0.1000E-5    eV    # [ELPH] Energy treshold for DW denominator
% ElPhModes
  1 |  3 |                   # [ELPH] Phonon modes included
%
GDamping=  0.10000     eV    # [GW] G[W] damping
dScStep=  0.10000      eV    # [GW] Energy step to evaluate Z factors
ExtendOut                    # [GW] Print all variables in the output file
ElPhRndNq= 2                 # [ELPH] Read random Q-points
RandQpts=0                   # [RIM] Number of random q-points in the BZ
WRgFsq                       # [ELPH] Dump on file gFsq coefficients
NewtDchk                     # [GW] Test dSc/dw convergence
%QPkrange                    # [GW] QP generalized Kpoint/Band indices
  1|  2|  1| 50|
%

In the QP file you see that LDA and HF are simply zero, why ?
From time to time i see unphysical Z factor (larger than 1), why ?

Sorry for the questions.
Best wishes
Martin

[martinspenke]

Dear Alejandro,

Just wanted to add that when i want to generate s.dbph data base for my system for production run, i end up with the following error when executing ypp_ph :

Code: Select all

<01m-23s> ELPH databases (WRITE) |###                                     | [008%] 01m-21s(E) 16m-16s(X)forrtl: severe (24): end-of-file during read, unit 41, file /tmp1/martin/pho/elph_dir/././s.dbph_000003
Image              PC                Routine            Line        Source             
ypp_ph             000000000074E5D9  Unknown               Unknown  Unknown
ypp_ph             00000000007731D4  Unknown               Unknown  Unknown
ypp_ph             000000000040F5B9  Unknown               Unknown  Unknown
ypp_ph             000000000040CBB6  Unknown               Unknown  Unknown
ypp_ph             000000000040B1D0  Unknown               Unknown  Unknown
ypp_ph             0000000000405E65  Unknown               Unknown  Unknown
libc.so.6          00007F9063D31A15  Unknown               Unknown  Unknown
ypp_ph             00000000004050E9  Unknown               Unknown  Unknown

Best wishes
Martin