The ABINIT Users Mailing List ( CLOSED )

[verstraete@pcpm.ucl.ac.be]

Hello Liu Lei,

The electron-phonon interaction in abinit is still very experimental, but 
some things do work. You should be familiar with the appropriate 
litterature, and read the preliminary user's guide in

Infos/elphon_manual.ps

- I'm afraid I definitely do not have the time to explain the inner 
workings of elphon or the theory.

The code and input variables are still evolving fast. In particular, the 
version I committed for 4.5.2 does not work:

lines 846-861 and 871-874 of Src_7ddb/read_gkk.F90 must be uncommented.

The best would be to wait for v4.6, which will also have more input 
variables, a debugged tetrahedron method, etc... In the meantime you can 
calculate all the phonon perturbations and extract the GKK files (see 
also the bug fix from James Raynolds for mrggkk).

You mentioned in a mail you wanted to look at MgB2. Magnesium diboride is 
a very anisotropic material, and for the moment abinit only does isotropic 
calculations, averaged over the Fermi surface. This is woefully inadequate 
to represent the coupling or Tc, as has been shown in the litterature. 
Plus, you need very dense kpoint meshes and largeish cutoffs for Mg and B.

Matthieu

--
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Matthieu Verstraete             mailto:verstraete@pcpm.ucl.ac.be 
PCPM, Boltzmann, pl. Croix du Sud, 1        tel: +32 10 47 33 59
B-1348 Louvain-la-Neuve  Belgium            fax: +32 10 47 34 52