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Band structure with hse06
Posted: Sun Mar 26, 2023 9:58 pm
by shishir1
I am getting band structure shift upward with hase06. Fermi energy is not at zero.
Please help me to get the correct band structure. I have attached the files here.
Re: Band structure with hse06
Posted: Tue Mar 28, 2023 9:40 am
by henrique_miranda
Could you share a figure with the band structure so I understand what you mean?
Do you have a semiconductor or a metal?
Re: Band structure with hse06
Posted: Tue Mar 28, 2023 3:09 pm
by shishir1
henrique_miranda wrote: ↑Tue Mar 28, 2023 9:40 am
Could you share a figure with the band structure so I understand what you mean?
Do you have a semiconductor or a metal?
band_hse2.png
here is the figure. The structure is heterostructure of graphene/Mos2.
Re: Band structure with hse06
Posted: Tue Mar 28, 2023 4:27 pm
by henrique_miranda
Ok, now I understand.
VASP does not shift the eigenvalues so that the fermi energy is at zero. You need to do that yourself.
The value of the fermi energy is reported in the OUTCAR file.
Re: Band structure with hse06
Posted: Tue Mar 28, 2023 8:45 pm
by shishir1
I tried the same with pure Graphene but there is the shift of Fermi at 0 with and without hse06. Even calculating Band Structure for Graphene/MoS2 without hse06 the Fermi is at zero.
band.png
Re: Band structure with hse06
Posted: Thu Mar 30, 2023 2:45 pm
by henrique_miranda
Did you shift the eigenvalues according to the fermi energy?
Which tool are you using for plotting?
Re: Band structure with hse06
Posted: Fri Mar 31, 2023 3:22 pm
by shishir1
No I didn't shift it for pure graphene. The fermi was exactly at zero for graphene with HSE06. I used origin to plot.
Re: Band structure with hse06
Posted: Mon Apr 03, 2023 11:50 am
by henrique_miranda
Ok, could you share the OUTCAR of the two calculations for which you posted the band structure?
[EDIT] OK, I think I know what the problem is: you need to get the fermi energy from an SCF calculation on a regular grid to shift the eigenvalues from your NSCF calculation.
Have a look at the line "Fermi energy:" in your OUTCAR file.
If you don't want to do two separate runs of VASP you might consider using the KPOINTS_OPT file perform an NSCF calculation along a path starting from the density you obtained in the SCF calculation.
The procedure is described on this page:
wiki/index.php/Band-structure_calculati ... unctionals
Re: Band structure with hse06
Posted: Fri Apr 14, 2023 1:16 am
by shishir1
Here are the BAND.dat and OUTCAR for graphene/MoS2 with and without hse06.
Re: Band structure with hse06
Posted: Fri Aug 18, 2023 8:34 am
by henrique_miranda
The tool you are using to produce the BAND.dat file is shifting the eigenvalues according to the fermi energy.
band/OUTCAR
Code: Select all
Fermi energy: 2.0543352579
k-point 1 : 0.0000 0.0000 0.0000
band No. band energies occupation
1 -17.0268 2.00000
band/BAND.dat
Code: Select all
#K-Path(1/A) Energy-Level(eV)
# NKPTS & NBANDS: 60 512
# Band-Index 1
0.00000 -19.081153
This last value -19.081153 is -17.0268-2.0543352579
The same goes for the file in band_hse/OUTCAR:
Code: Select all
Fermi energy: 0.8727577133
k-point 1 : 0.0000 0.0000 0.0000
band No. band energies occupation
1 -19.5942 2.00000
band_hse/BAND.dat
Code: Select all
#K-Path(1/A) Energy-Level(eV)
# NKPTS & NBANDS: 15 294
# Band-Index 1
0.00000 -20.466959
which again -20.466959 is -19.5942-0.8727577133.
In the case of HSE, you are doing a regular grid + zero weight k-points. The fermi level in this case should be the correct one.
For PBE it looks to me like you are doing a NSCF calculation along a path. In this case, the fermi level is not correct.
You need to compute the fermi level on a regular grid. That's why I suggested using the Fermi level from the SCF calculation.
I hope this helps!