[Wien] missing electrons

[Peter Blaha]

> I realise I had similar problems recently. In order to simulate
> photoemission spectra,  the density of states along the Gamma-X
> direction was needed. Since Wien integrates over the whole Brillouin
> zone, I decided to take three points along the Gamma -X direction
> (Gamma, X/2,X) separately and then add the DOS taking into account  the
> weight of each k-point. Unfortunately due to the problem with
> Delta-functions you discuss below, tetra produced no output for the
> single k-points. Is there an alternative way of getting the DOS along a
> particular direction in BZ?

Not directly implemented in WIEN, but you could do it yourself:

I see two simple possibilities:

Always use a special k-mesh (eg. Gamma-X)

a) Histogram method (this was done in pre-tetra times). Define a E-mesh
with a certain delta-E. Now check all your eigenvalues in which
E-intervall (histgram block) they fall and increase the histogram-counter
by the weight of this k-point.
It will give a very "spiky" DOS, probably you can smooth it afterwards.

b) Quite similar (or equivalent?), only the smoothing is done first.
Take each eigenvalue (+weight) and broaden it with some Gaussian. Add this
Gaussian to the DOS and sum up.

Regards

                                      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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