[Pw_forum] Fermi energy in 'scf' and 'nscf'

Hande Ustunel hande at newton.physics.metu.edu.tr
Wed Aug 13 07:34:46 CEST 2008

Dear Guoying,

>             scf:           k-mesh grids   10*10*10  (282kpoints in
> *.scf.out file)
>           nscf:           we give 121 kpoints along high symmetry direction

In order to find the Fermi energy, the code performs an integration in
k-space and this integration is of course numerically performed over the
kpoints you provide. In the nscf run, you provide a highly heterogeneous
set of kpoints so the Fermi energy you get is not the same as the scf
solution where the BZ is sampled more evenly (and also more densely in your
case). As a result, you should trust the scf result.


Hande Toffoli
Department of Physics
Office 439
Middle East Technical University
Ankara 06531, Turkey
Tel : +90 312 210 3264

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