Dear all,
I am trying to do el-ph calculations only at the Gamma point for graphene (as I
want to compare it to another system where the calculations are only feasible
at the Gamma point). However the values I am getting for lambda for graphene
AT THE GAMMA POINT are really high:
degauss lambda
0.005
13.442600 0.015 2.303600 0.020 1.756000
0.025
1.436000
0.030
1.228800
0.035
1.085800
0.040
0.983000
0.045
0.906400
0.050 0.847800I am using a 90 x90 x1 grid (in scf) for graphene.
It is already known that lambda for graphene is ~0.02. (1) Do the above
results mean that one cannot calculate el-ph coefficients unless on a grid of
phonons and then are the calculations -at the Gamma point ONLY- useless and
unexact?
(2) or does this mean that the results did not converge due to a small k-mesh
in the scf calculations (90x90x1) and I need to increase it to say 400x400x1?
Any suggestions of any kind would also be ahighly appreciated.
Thanks for your help
Elie MUniversity of NottsNG7 2RDUK
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