[Wannier] Generating .mmn matrix for all pais of k-points

[Vahid Askarpour]

Dear Dominik,

Thank you so much for your quick response. I will follow your suggestions.

Best wishes,

Vahid

On Mar 16, 2017, at 8:35 PM, Dominik Gresch <greschd at phys.ethz.ch<mailto:greschd at phys.ethz.ch>> wrote:


Dear Vahid,

You can use the 'nnkpts' parameter (new in version 2.1) to explicitly specify for which k-point pairs the overlap should be calculated. This just side-steps the way that Wannier90 tries to calculate the nearest neighbours, and prints the neighbours you supply directly to the .nnkp file. To get the .mmn output for all pairs of k-points, you could generate the nnkpts block such that it includes all the overlaps you need.

For the interface to QE, you need to use the 'regular_mesh = .false.' when using pw2wannier90 to allow for non-regular k-grids to be used (new in QE v.6).

Best regards,

Dominik Gresch

On 17.03.2017 00:13, Vahid Askarpour wrote:
Dear Wannier Community,

I am attempting to include impurity scattering rate calculation in the EPW calculation. At present, EPW determines the scattering rates only due to electron-phonon scattering.

To include impurity scattering, one needs the overlap intergal for the lattice-periodic part of the wave function |u_nk> between any two k-points. The .mmn files creates such a file but it is only for the nearest neighbor k-points. Before attempting to redo a separate code, I have two questions:

1. Is it possible to output the .mmn file for all pairs of k-points?

2. Is it possible to do 1 not for a k-grid but for a list of random k-points? I suspect this can be done using


begin kpoints
# of k points
…
…
end kpoints

and the same k-points must be used in the preliminary self-consistent and non self-consistent calculations with QE.

I ask question 2 because for thermoelectric properties, one needs to select k-points with energies  ~0.5 eV above the CBM. So it is possible to generate a very dense k-grid (100^3) and only include the selected k-points in the impurity scattering rate calculation.

I would appreciate your help with the above questions.

Vahid

Vahid Askarpour
Department of Physics and Atmospheric Science
Dalhousie University,
Halifax, NS, Canada



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