Hi all,
I am following this to calculate bandgap of Si using HSE06 in: VASP:https://www.vasp.at/wiki/index.php/Si_bandstructure
in step-1. I am running a SCF caculation using PBE. For which I have used this INCAR
System Si
IBRION = -1
NSW = 0
ISMEAR = 0
SIGMA = 0.01
ENCUT = 520
ALGO = Accurate
EDIFF = 1E-6
PREC =H
in the second step, along with POSCAR,POTCAR,KPOINTS used the WAVECAR file of the previous step as input and the INCAR file is :
System Si
LHFCALC = .TRUE.
HFSCREEN = 0.2
ALGO = D
TIME = 0.4
ENCUT = 520
ISMEAR = 0
SIGMA = 0.01
GGA = PE
and then I used the script gap.sh that is also provided in vaspwiki examples to calculate HOMO and LUMO.
But the HOMO is now coming approx 0.13ev and the LUMO is -0.78ev .
Please tell me what I have done wrong.
Thanks in advance.
Hi Joyeta Saha
Although i have never tried this script, but you can do a test,
Export the data of bands from vasprun.xml using P4vasp in .dat format,
and identify the KPOINTS from which your actual bands are starting.
As in HSE band structure, bands at initial KPOINTS are random which are taken from the IBZKPT file. Real band structure is from the point, where you provided the high symmetry path. like in this example at https://www.vasp.at/wiki/index.php/Si_bandstructure
Explicit k-points list 18
In the beginning the kpoints file is not suitable first use seekpath or vaspkit to get the zero points after that you take the points from the IBZKPT file and add them in the place of the non-zero points in the file of the KPOINTS you created on the SEEKPATH and rewrite the number of total points you have at the top of the file
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