[Wien] Band Labeling

[Peter Blaha]

One labels them according to the irreducible representations.

Use "irrep" to calculate those representations (for non-symmorphic SG only).

> How do we label the bands in the band structure that we have calculated
> for some compound? I have read up some materials on the subject, but till
> now I have been able to get some rumor level ideas only. Can some body
> please point out some good references for the topic, and lay out some
> algorithm as to how to go about it practically? The band structures that I
> am talking about are for tetragonal materials the data for which is not
> available do readily in literature.
>
> Questions are:
>
> 1. How do we get the block matrix and irreducible representations of the
>    Hamiltonian matrix?

We do not use symmetry decomposition of the hamilton matrix. It is of course
correct that in principle one can do this (and it was done in APW some 30-40
years ago). Nowadays, with low (no) symmetry it does not pay off anymore.

> 2. How do we assign to the bands the labels based on the point group
>    operations for some symmetry point?

See my comments at the top.y

                                      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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