ANADDB calculation of electron-phonon

Phonons, DFPT, electron-phonon, electric-field response, mechanical response…

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venky
Posts: 3
Joined: Fri May 04, 2018 6:12 pm

ANADDB calculation of electron-phonon

Post by venky » Fri Jun 22, 2018 6:38 pm

Dear all,
I am using abinit 8.6.3 and I am following the tutorial on electron-phonon coupling step by step. I obtained the gkk files, ddb files and merged them using the mrggkk, mrgddb utility as described in the tutorial. Next I am moving to the ANADDB calculation of electron-phonon (step4 in the tutorial https://docs.abinit.org/tutorial/eph/), I got a Error like this

--- !ERROR
src_file: read_gkk.F90
src_line: 269
mpi_rank: 0
message: |
found too many qpoints in GKK file wrt anaddb input
nqpt_anaddb nqpt_gkk = 4 5
...

Here, i am uploading my input
Thanks a lot in advance for your help
Attachments
MLG_1.in
Graphene monolayer for calculating the gkk and ddb files.
(5.58 KiB) Downloaded 281 times
MLG_4.in
electron-phonon quantities.
(1.51 KiB) Downloaded 269 times

mverstra
Posts: 655
Joined: Wed Aug 19, 2009 12:01 pm

Re: ANADDB calculation of electron-phonon

Post by mverstra » Sat Jun 23, 2018 12:47 pm

Hi,

lots of things: you will want to adapt the q grid to the 2D hexagonal system. right now you left 2x2x2 (3D grid, and not a multiple of 3, so no K point in electrons or phonons).

Then, anaddb expects files containing _exactly_ the qpoints on the irreducible grid it generates from ngqpt + shiftq=0 0 0. You have many more because 1) the system is hexagonal and not cubic 2) you should not have q points or k along the z axis.

To get the irreducible q point set, in abinit use:
qptopt 1
shiftq 0 0 0
iqpt2 1
iqpt3 2
etc..
idem for DS 12 13 14

And to know when to stop you can do a pre-run with a k-point grid of
ngkpt n n n shiftk 0 0 0 kptopt 1
in a separate directory, kill the job once it has printed the header and check nkpt. Alternately, if you ask for iqpt > nqpt in a phonon run, the code will stop.

Finally, there is also a new driver for electron phonon stuff, check out the abipy tutorials on that topic.
Matthieu Verstraete
University of Liege, Belgium

venky
Posts: 3
Joined: Fri May 04, 2018 6:12 pm

Re: ANADDB calculation of electron-phonon

Post by venky » Tue Jun 26, 2018 8:48 am

Hi,
Thank you very much for your reply.
Again, I got one error like.

Information is missing in the DDB.
The dynamical matrix number 4 cannot be built,
since no block with wavevector 5.000000E-01 5.000000E-01 0.000000E+00
has been found.
Action: add the required blok in the DDB, or modify your input file.
How to add the above DDB block?
If i am using variable reduced coordinates iqpt ...
Here, i upload the input file.
Thank you in advance.
Attachments
MoS2_1.in
Input file for MoS2 monolayer.
(6.89 KiB) Downloaded 270 times

mverstra
Posts: 655
Joined: Wed Aug 19, 2009 12:01 pm

Re: ANADDB calculation of electron-phonon

Post by mverstra » Tue Jun 26, 2018 10:18 am

you are missing the iqpt for the DS 12 13 14 etc.. I think. Perhaps start with a "simple" anaddb run, without eph, to check if the DDB is actually complete. Get a BS and DOS. The elph module is more difficult about having exactly what it asks for in the DDB and GKK files.
Matthieu Verstraete
University of Liege, Belgium

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