[Pw_forum] positive Fermi energy

[Paolo Giannozzi]

On Oct 24, 2010, at 12:07 , david grifith wrote:

> yet I have not understood where is selected as zero energy
> in the Bulk graphite by QE ?  or generally where is selected
> as zero energy in QE calculations?

nothing is selected as "zero energy". One-electron energies,
including the Fermi energy, are calculated with respect to some
arbitrary reference energy (see the paper cited in the first of
the following links). If you want to set your zero of the energy
at the Fermi energy, you can do it in your preferred plotting
program. If instead you want to know how this arbitrary reference
level is calculatd in the code, see the notes in the last link.

http://www.democritos.it/pipermail/pw_forum/2004-August/001240.html
http://www.democritos.it/pipermail/pw_forum/2007-April/006351.html
http://www.democritos.it/pipermail/pw_forum/2009-June/013231.html
http://www.democritos.it/pipermail/pw_forum/2009-June/013232.html

P.
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Paolo Giannozzi, Dept of Chemistry&Physics, Univ. Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222