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

[L. D. Marks]

If you use temperature broadening, this would put E_f in the middle of the 
gap.

On Wed, 3 May 2006, Peter Blaha wrote:

> 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
>>
>>
>>
>> ---------------------------------
>> Yahoo! Messenger with Voice. PC-to-Phone calls for ridiculously low rates.
>
>
>                                      P.Blaha
> --------------------------------------------------------------------------
> 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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-----------------------------------------------
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2225 N Campus Drive
Northwestern University
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Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
http://www.numis.northwestern.edu
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