[Wien] Bandgap values in hybrid calculations.

[Laurence Marks]

I am not certain that your question has an answer. You may just be killing
defenseless electrons without reason.

Critical is the question of what are you trying to do:
a) Perform a good calculation to support your (or other people's)
experimental measurement?
b) Disprove some other calculation?
c) Find what parameters approximate best the experimental band gap and then
use these for something else?

Increasing both the number of bands and k-points (bands perhaps more) will
improve the convergence of the calculation. Without context it is hard to
give a definitive response.

_____
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu

On Tue, Dec 29, 2020, 06:12 Serhat Ayık <aserhatayik at gmail.com> wrote:

> Dear wien2k users,
>
> I calculated the energy band gap values using the hybrid function
> (YS-PBE0).
>
> The k-point value in one calculation is 4 * 4 * 4, in another calculation
> is 6 * 6 * 6.
>
> I wrote the nband number as occupied+1 in both calculations.
>
> The energy band gap in the second calculation, where the k-point 6 * 6 *
> 6, turned out to be closer to the experimental data. (calc. : 2.9eV, exp.:
> 3.1ev)
>
> What should I do to approximate the energy band gap values I find in
> hybrid calculations to experimental data?
>
> Should I increment the k-point or the number of nbands?
>
> Best regards
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