Bandstructure using HSE06 functional

[deepashri]

Dear All,
I am trying to calculate the bandstructure of PtS2 monolayer using HSE06 functional. Upon doing a self-consistent calculation with a dense k-mesh, I add following lines in the INCAR file to perform non-self consistent run :

LHFCALC = .TRUE.
HFSCREEN = 0.2
AEXX = 0.25
ALGO = D
TIME = 0.4
LDIAG = .TRUE.

The KPOINTS file is also changed as per the IBZKPT file with some extra points added at the end. The bandstructure is then plotted for only the extra points added. Although I get a larger band-gap with the use of hybrid functional, the nature of bands looks slightly different than that in the bandstructure calculated using PAW-PBE functional. e.g. some bands look flat and the dispersion is lost. What could be the reason for this?

Thanks in advance.

[jmullen]

Hello,

I am learning how to do the same activity (plotting band structure with hybrid functional) and have similar problems after following the manual and tutorials. So far, I am seeing improvement by increasing NELMIN well above the recommended 5 in the manual. I have not completed the task yet, so I cannot say with confidence that this is the solution to my problem, but it is showing improvement.

Hope this helps

Jeff Mullen
NCSU

[deepashri]

Thank you very much for the reply.
I could get rid of the problem by using a denser k-mesh.
But the higher unoccupied bands are still not "looking" good. First two unoccupied bands are exactly similar to that in the bandstructure using PBE functional (but at a higher energy). Any suggestions?

Best,
Deepashri.

[jmullen]

Did you try to increase the NELMIN value ?