[QE-users] Possibility of shifting energy for band structure plotting using HSE functional

[Giuseppe Mattioli]

Dear Shivesh Sivakumar

You can do whatever you consider appropriate, as long as you discuss  
it with all the details in the appropriate methods section of your  
manuscripts. However, delocalization errors at not limited only to the  
underestimation of the ionization potential and electron affinity  
(i.e., of the band gap). Hence, the usage of HSE is recommended, but  
the final choice depend on which property of your 2D materials are  
inrerested in.
HTH
Giuseppe

Quoting Shivesh Sivakumar <shiveshsivakumar at gmail.com>:

> Hello all,
>
> I was performing a PBE calculation for a 2-D material and I found out the
> bandstructure. However, since Kohn-Sham DFT underestimates bandgap, I
> implemented the HSE functional to do an scf calculation and found out how
> much my band gap has increased. Is it now possible for me to just manually
> account for this adjustment in the bandstructure obtained from PBE ? I'm
> curious because HSE calculations are turning out to be quite expensive
> depending upon the density of mesh for the Fock operator.
>
> To summarize, is it possible to shift the energy levels in my PBE
> bandstructure to account for the bandgap increase I determined from the HSE
> scf output? (Since HSE doesn't change the wavefunctions, and causes only a
> rigid shift?)
>
> Any insights would be much appreciated.
>
> Best,
> Shivesh Sivakumar



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