Search found 616 matches

by sponce
Thu Jan 18, 2024 1:59 pm
Forum: General discussion
Topic: Why do we need to run self-consistent calculation twice?
Replies: 2
Views: 1523

Re: Why do we need to run self-consistent calculation twice?

Hello,

We like to decouple things so that everything is clear.
In principle it is indeed not needed and the following should work
scf.in
ph.in
pp.py
nscf.in
epw.in

Best wishes,
Samuel
by sponce
Tue Nov 14, 2023 1:45 pm
Forum: Running the code
Topic: Error: Problem with modes file
Replies: 2
Views: 5372

Re: Error: Problem with modes file

Hello, This means that there is an incompatibility between your phonon calculation (dvscf files) and the current EPW calculations. Note that the new version of EPW v5.8 (to be released very soon) will include support for 2D materials. You can already download the development version here if you are ...
by sponce
Tue Nov 14, 2023 1:41 pm
Forum: Electron-phonon
Topic: EPW calculations for a magnetic structure
Replies: 1
Views: 6659

Re: EPW calculations for a magnetic structure

Dear Nasrin, Indeed EPW does not support magnetic calculations. You can try running EPW without magnetism as an approximation. You can read external eigenvalues (.eig files), such as from calculations made with HSE. It will not impact the electron-phonon matrix element directly but will have an impa...
by sponce
Tue Nov 14, 2023 1:29 pm
Forum: General discussion
Topic: 2023 Virtual School on Many-Body Calculations using EPW and BerkeleyGW
Replies: 2
Views: 19055

Re: 2023 Virtual School on Many-Body Calculations using EPW and BerkeleyGW

Dear Pravin Karna,

As indicated in the tutorial, you need to use QE 7.2.

Best wishes,
Samuel
by sponce
Tue Nov 14, 2023 1:28 pm
Forum: Theory
Topic: Mobility calculation of materials with flat bands using EPW
Replies: 4
Views: 14107

Re: Mobility calculation of materials with flat bands using EPW

Hello Muhammad,

The code will work and produce results.

However if the band is too flat, the BTE theory is indeed not expected to hold.
In that case you will likely create polaron etc.

I would therefore be very cautious with very flat band materials.

Best wishes,
Samuel
by sponce
Tue Sep 19, 2023 7:18 am
Forum: General discussion
Topic: Defining positive-definite homogenous K-point grid for EPW calculations
Replies: 2
Views: 6981

Re: Defining positive-definite homogenous K-point grid for EPW calculations

Dear Muhammad Aminul Haque, Welcome on the EPW forum ! First, it is recommanded to use the same multiplicative factor between the coarse k-point and q-point grid. Therefore if you have a 4x4x2 q-point grid, you can have a 8x8x4 grid or 12x12x6 k-point grids. The pw.x code in calculation mode "nscf" ...
by sponce
Thu Jul 06, 2023 1:43 pm
Forum: Running the code
Topic: BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
Replies: 2
Views: 2455

Re: BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES

Hello,

It seems that the inputs could be fine.
Could you provide the full backtrace of the problem ?

Thanks,
Samuel
by sponce
Thu Jul 06, 2023 1:39 pm
Forum: Running the code
Topic: Tutorial of phononlifetime
Replies: 2
Views: 11317

Re: Tutorial of phononlifetime

Hello,

It is indeed the Phonon linewidth, expressed in meV.
The factor to go from energy, expressed in Ry to a rate in 1/ps is 20670.6944033.

Best wishes,
Samuel
by sponce
Thu Jul 06, 2023 1:31 pm
Forum: General discussion
Topic: Calculating electron-phonon coupling with finite difference method
Replies: 1
Views: 16360

Re: Calculating electron-phonon coupling with finite difference method

Dear Haiyang, Since you are here comparing the k=[0 0 0] and q=[0 0 0], I would first print the electron-phonon matrix element directly from the ph.x code. Note that this can now be done using the Quantum Espresso develop version - https://gitlab.com/QEF/q-e/-/merge_requests/2116 If this is working,...
by sponce
Tue Jul 04, 2023 1:08 pm
Forum: Theory
Topic: Difference between vme = dipole and vme = wannier
Replies: 1
Views: 15181

Re: Difference between vme = dipole and vme = wannier

Dear Félix, vme = 'dipole' corresponds to Eq. 24 from the paper that you mention. vme = 'wannier' corresponds to Eq. 27 from the PRR paper. Both are equivalent when Wannier functions are well converged. In case where the Wannier function are not perfect, vme = 'dipole' is expected to be more accurat...