Page 1 of 1

Electron occupation above Fermi level

Posted: Fri May 15, 2009 2:38 pm
by mhyman
I was playing around with some calculations (CO on Pd) and noticed electron occupation above the Fermi level.

This is at the Gamma point from the PROCAR file
band 65 # energy -2.42400903 # occ. 1.44859128
band 66 # energy -2.30254805 # occ. 0.79238998
band 67 # energy -2.26017041 # occ. 0.57352785
band 68 # energy -2.10547569 # occ. 0.09757602

And the Fermi level is...
E-fermi : -2.3398

I thought that the Fermi level of a metal was the highest energy electron occupied state at 0K. The above data suggest otherwise.

Furthermore, looking at the band decomposed electron density for band 72, which should have zero electron occupation

band 72 # energy 0.44149605 # occ. 0.00000000

However, there is electron density in this band.

I'm sure there's an explanation for the fact that there is electron density well above the Fermi level that I'm not understanding, right? Please help me out here.

Electron occupation above Fermi level

Posted: Mon May 18, 2009 2:43 am
by giacomo giorgi
I would try a Fermi smearing approach with a very reduced value of sigma

ISMEAR=-1 e SIGMA = 0.002 (i.e., ~ 0.0)

best,
g