[Wien] Energy level

[Lukasz Plucinski]

Dear WIEN users,

Can the Fermi-energy (Fermi level) calculated by LAPW2 lie within the
optical gap?

I understad that this question may already appear many times - I am sorry.

Why I ask: in photoemission experiment one can mount 2 samples on the
same sample holder such that they are in electrical contact. If one of the
samples is metallic and other semiconducting one can measure that the
Fermi edge of this system lies within the optical gap of the
semiconductor. Can WIEN calculate this position? I suppose not, but would
like to be sure. I suppose WIEN is just putting the Fermi-level on last
occupied band such that it is always at the VBM for semiconductors.

I also noticed that the width of the bulk valence band is smaller in slab
calculation (15 layers slab separated with 15 A of vacuum) than in bulk
calculation by around 0.5 eV (although shape of projection is like in
bulk calculation). Can I consider this as correct behaviour related to
the fact that slab is actually only approximating real system?

Regards,

Lukasz



PS. To moderator: This e-mail will probably be stopped and will have to
wait for moderator decision. This is because my e-mail appears as
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(buphy.bu.edu is the same physical machine as physics.bu.edu). I don't
know how to change it in 'pine', if possible please my e-mail in
your registry to pluto at buphy.bu.edu.