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

[Shivesh Sivakumar]

Giuseppe,

Thanks very much for your input.

Best,
Shivesh Sivakumar

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On Mon, Apr 20, 2020 at 8:43 AM Giuseppe Mattioli <
giuseppe.mattioli at ism.cnr.it> wrote:

>
> 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
>
>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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> E-mail: <giuseppe.mattioli at ism.cnr.it>
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