[Wien] Fermi level after mBJ calculation

[Parker, David S.]

For an insulator, finding the VBM can require plotting of the Fermi
surface at some doping using xcrysden or something else, if the maximum is
not at a symmetry point, which happens sometimes.

On 10/26/12 12:58 PM, "Peter Blaha" <pblaha at theochem.tuwien.ac.at> wrote:

>Clearly, you should in general NOT use EF from case.scf2up in a band
>structure calculation.
>In particular when your system is METALLIC, with a "bandstructure k-mesh"
>one cannot perform a
>good BZ integration and EF will be wrong!
>Of course, you have to increase the regular k-mesh of the scf runs, until
>EF is stable.
>
>Of course, the situation may be different for an insulator because
>in the scf k-mesh due to "shifted k-meshes", the VBM may not be in your
>mesh and thus you may miss
>the highest occupied state. Eventually you will have the VBM in your
>bandstructure mesh
>(eg. the Gamma point), but there are numerous cases, where the VBM can
>also somewhere in
>the BZ and NOT at a high symmetry point.
>Thus for an insulator, I'd call the proper EF as the highest energy you
>can get of the l
>ast occupied band.
>
>
>
>Am 26.10.2012 18:42, schrieb Kamil Klier:
>> Colleagues,
>>
>> Please advise whether, following a converged LDA+U and mBJ calculation,
>>the Fermi energy to be inserted into case.insp after the sequence:
>>
>> x lapw1 -c -p -up -band
>> x lapw1 -c -p -dn -band
>> x lapwso -c -orb -p -up
>> x lapw2 -c -so -p -qtl -up -band
>> x lapw2 -c -so -p -qtl -dn -band
>>
>> is to be found from case.scf2up/dn (grep :FER case.scf2up), not from
>>previously saved case.scf (cf. paragraph 8.3.2, line 9, efermi in the
>>Wien2k manual).
>>
>> The -band calculation uses different number of k-points read from
>>case.klist_band (e.g. 61 k-points for the hcp list) than the preceding
>>mBJ calculation with fewer
>> k-points. Is this the reason for the difference between :FER from
>>case.scf and case.scf2up/dn?  Would the difference be removed if
>>case.klist and case.klist_band were
>> identical?
>>
>> Thanks,
>>
>> Kamil Klier
>> Lehigh University
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>
>-- 
>-----------------------------------------
>Peter Blaha
>Inst. Materials Chemistry, TU Vienna
>Getreidemarkt 9, A-1060 Vienna, Austria
>Tel: +43-1-5880115671
>Fax: +43-1-5880115698
>email: pblaha at theochem.tuwien.ac.at
>-----------------------------------------
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