[Wien] irreducible representation

[Peter Blaha]

> I want to calculate bandstructure of the compound in s.g. I4/m 
> (symmorphic s.g.) and I executed the lapw-1-band and then irrep and 
> finally spaghetti. During this calculation, no error is reported. 
> However, when I want to plot my final bandstructure, I only get it in 
> direction gamm-X-M. For other directions like M-N-P-gamma there is 
> nothing. The possible explanation would be the following what is written 
> in the manual:"It will not work in cases of non-symmorphic spacegroups 
> AND k-points at the surface of the BZ." So, for k-points at the surface 
> of BZ it will not work, and therefore I can not obtain such irreducible 
> representation of BS for mentioned directions. Is it correct?

No. irrep should work for all symmorphic symmetries.

Only for k-points in non-symmorphic cases at the surface of the BZ 
higher dimensional irreps (eg. 4 fold) can appear and require 
grouptheory not implemented in irrep.




> My second enquiry is concerned primitive Brillouin zone of primitive 
> body centered tetragonal cell. In my case for the same s. g. lattice 
> parameters are c= 3.0 A, a =10.4 A, and if one use the programme 
> Xcrysden to draw Brillouin zone, for conventional tetragonal I-centered 
> lattice it looks OK (C*>a,b*), but in a case of primitive Brillouin zone 
> one obtains c*<a*,b*. However, according to my calculation it should be 
> also opposite like in conventinal Brillouin zone case. I attach the 
> primitive BZ obtained by crysden.
> Regards,
> Igor
> 
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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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