[Wien] kgen and kgen -fbz

[Dr. K. C. Bhamu]

Dear Wien2k Users


I have a doubt for x kgen  and need some clarification.
For calculating DOSS and optical properties we need a fine mesh and many
numbers of k points for thermoelectric properties.

What we observed that: If we use only x kgen with 2000 k points, we get 72
kpoints with 12 12 12 mesh siz (in our case otherwise it depends on the
case).

If I use x kgen -  fbz it gives 1728  total number of k-points with same
mesh size (12 12 12).

For thermoelectric properties, if I use "x kgen" for 40000 k points, it
gives me 1059k-point with a 34 34 34 mesh size while with kgen -fbz I am
getting 39304 k-point with same mesh size 34 34 34.



As far as I know  "x kgen" represents the IBZ which gives image mapping of
full BZ with 3D repetition while kgen with -fbz stands for whole BZ.
.
My query is:

Which type of BZ I should use for thermoelectric, optical and DOSS. If I
use 40000 kmesh with -fbz it takes much more time.

Would there be any difference for simply "x kgen" or "x kgen -fbz"
calculations?



Bhamu
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