Fermi level

Total energy, geometry optimization, DFT+U, spin....

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zjuer
Posts: 42
Joined: Thu Feb 17, 2011 2:05 am

Fermi level

Post by zjuer » Tue Aug 16, 2011 6:24 pm

Hello all,

I found the the Fermi energies from SCF, Fermi surface, DOS calculation are a bit different. Then my question is Why all the Fermi energies are not identical for the same system, which one should I use? Thanks a lot.

Zjuer

wenzhouchen
Posts: 3
Joined: Thu Sep 08, 2011 2:55 pm

Re: Fermi level

Post by wenzhouchen » Wed Sep 14, 2011 3:34 am

Hellow,
The Fermi energy can get from the output file, but i want to know how do you gt the Fermi surface?

blackburn
Posts: 42
Joined: Fri Aug 14, 2009 8:03 pm

Re: Fermi level

Post by blackburn » Wed Sep 14, 2011 2:28 pm

To get the Fermi surface in BXSF format (for XCrysDen), you can use the prtfsurf variable. However, you can only it with a non-shifted k-grid.

The 3 different Fermi levels you get are probably due to different k-grid. You need a very dense k-grid in a metal because of the Fermi surface (this is more important in some system than in others). I think you should use the Fermi levels from the calculation with the most k-points. If the difference between the three values is significant, you should consider rerunning the calculations with more k-points.

Simon

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