[Wien] Why Fermi energy is in the middle of the band gap?

[Peter Blaha]

For some older WIEN version it could happen, that due to numerical
rounding EF is  a) at the bottom of the conduction bands
b) a little larger than the top of the valence band (a few mRy).
This should not occur with the latest version.

I've never seen EF "in the middle of the gap".

For the bandstructure you have to put EF by hand into case.insp.
Maybe you inserted the wrong EF or the potential (clmsum) was from another
calculation,... or some similar error.

For the DOS you could set E-Fermi correctly in case.qtl, and you should get
EF from the "bandlimits" in case.scf (unless your DOS calculation uses
a different potential than the scf run.)

 

> Dear WIEN2K users:
>  When I plot the band structure of pure PbTe with the GGA of Engel-Vosko,
>  which is a "hidden" option (put 25 instead of 13 in case.in0), I found that
>  the band gap is about of 0.25ev, but the Fermi energy is in the middle of
>  the band gap. There is the same phenomenon in the DOS picture as it in
>  the band structure picture.
>  
>  Could anyone tell me why the Fermi energy is in the middle of the band
>  gap? How can I put the Fermi energy at the top of valence band?
>  My scf cycles with spin orbit coupling is well.
>  My wien version is WIEN2k_05_1020.
>  
>  
>  Thanks in advance and best wishes
>  
>   Joey Davis
>  
>  
> 		
> ---------------------------------
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                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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