[DFTB-Plus-User] Fermi energy for surface

[Bálint Aradi]

Dear Vladimir,

> 
> Yes I think so (but I have to check it). In my previous band structure
> calculations I found that the DOS picture shifted due to the changes in
> supercell vector (I think that the shift of Fermi level has the same value,
> because band gap is unchanged). But I interested in absolute value of Fermi
> level for surface. Can I shift my valence band for surface to the valence
> band for bulk and conclude that the Fermi level for surface also changes
> with respect of such shift?
> 

  The absolute value of the eigenlevels have no real meaning, as due to
the neglect of the core electrons we are using a sort of pseudopotential
like approach. As such, the Fermi level only has a meaning with respect
to the other eigenlevels obtained in the same calculation. There are of
course techniques to align bands obtained in different calcultions, like
calculating the branching point energy, have a look into the literature.

  Best regards,

  Bálint

-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/en/~b_aradi


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