Si HSE bandstructure
Description: Bandstructure for Si within DFT+HF
Bandstructure in VASP can be obtained following three different procedures. The standard procedure (procedure 1),
applicable at PBE level, is also described in Fcc Si bandstructure example.
Within Hybrid functional theory it is possible to plot bandstructure using procedure 2 or 3.
Procedure 1: Standard procedure (suitable for DFT calculations)
Only possible within DFT. Described in Fcc Si bandstructure example:
Standard self-consistent (SC) run
system Si 5.430 0.5 0.5 0.0 0.0 0.5 0.5 0.5 0.0 0.5 2 cart 0.00 0.00 0.00 0.25 0.25 0.25
- INCAR (see INCAR.dft)
ISMEAR = 0 SIGMA = 0.01 NBANDS = 8
- KPOINTS (see KPOINTS.6)
6x6x6 0 G 6 6 6 0 0 0
Non-SC calculation (ICHARG=11)
Use preconverged CHGCAR file and a suitable KPOINTS file
ISMEAR = 0 SIGMA = 0.01 NBANDS = 8 ICHARG = 11 #read charge from CHGCAR and keep fixed LORBIT = 11
- KPOINTS (see KPOINTS_PBE_bands)
k-points for bandstructure L-G-X-U K-G 10 line reciprocal 0.50000 0.50000 0.50000 1 0.00000 0.00000 0.00000 1 0.00000 0.00000 0.00000 1 0.00000 0.50000 0.50000 1 0.00000 0.50000 0.50000 1 0.25000 0.62500 0.62500 1 0.37500 0.7500 0.37500 1 0.00000 0.00000 0.00000 1
Plot using p4v
P4VASP: p4v
Procedure 2: 0-weight (Fake) SC procedure (works DFT & hybrid functionals)
This procedure can be applied to compute bandstructure at hybrid functionals and DFT level (see the HSE_bandstructure.sh script).
Standard DFT run
Just as before
- INCAR (see INCAR.dft)
ISMEAR = 0 SIGMA = 0.01 NBANDS = 8
- KPOINTS (see KPOINST.6)
6x6x6 0 G 6 6 6 0 0 0
Hybrid calculation using a suitably modified KPOINTS file
- INCAR (see INCAR.hse)
ISMEAR = 0 SIGMA = 0.01 LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; AEXX = 0.25 ALGO = D ; TIME = 0.4 ; LDIAG = .TRUE. EDIFF = 1.E-6 NBANDS = 8
- KPOINTS (see KPOINTS_HSE_bands.6 and README.txt)
Automatically generated mesh
26
Reciprocal lattice
0.00000000000000 0.00000000000000 0.00000000000000 1
0.16666666666667 0.00000000000000 0.00000000000000 8
0.33333333333333 0.00000000000000 0.00000000000000 8
0.50000000000000 0.00000000000000 0.00000000000000 4
0.16666666666667 0.16666666666667 0.00000000000000 6
0.33333333333333 0.16666666666667 0.00000000000000 24
0.50000000000000 0.16666666666667 0.00000000000000 24
-0.33333333333333 0.16666666666667 0.00000000000000 24
-0.16666666666667 0.16666666666667 0.00000000000000 12
0.33333333333333 0.33333333333333 0.00000000000000 6
0.50000000000000 0.33333333333333 0.00000000000000 24
-0.33333333333333 0.33333333333333 0.00000000000000 12
0.50000000000000 0.50000000000000 0.00000000000000 3
0.50000000000000 0.33333333333333 0.16666666666667 24
-0.33333333333333 0.33333333333333 0.16666666666667 24
-0.33333333333333 0.50000000000000 0.16666666666667 12
0.00000000 0.00000000 0.00000000 0.000
0.00000000 0.05555556 0.05555556 0.000
0.00000000 0.11111111 0.11111111 0.000
0.00000000 0.16666667 0.16666667 0.000
0.00000000 0.22222222 0.22222222 0.000
0.00000000 0.27777778 0.27777778 0.000
0.00000000 0.33333333 0.33333333 0.000
0.00000000 0.38888889 0.38888889 0.000
0.00000000 0.44444444 0.44444444 0.000
0.00000000 0.50000000 0.50000000 0.000
Please note that step two requires a WAVECAR obtained from a standard DFT run (not an HSE calculation), otherwise the resulting conduction bands often have a zig-zag structure.
Plot using p4v
P4VASP: p4v
Mind: Zoom in on the right-side part of the bandstructure plot.
Procedure 3: VASP2WANNIER90 (works for DFT, hybrid functionals, and GW)
Wannier function interpolation using the VASP2WANNIER90 interface: this procedure is applicable to DFT, hybrid functionals, and GW bandstructure calculations. Here we apply it for a hybrid functional. For GW see the Bandstructure of Si in GW (VASP2WANNIER90) and bandstructure of SrVO3 in GW examples.
To see a summary of the workflow below, have a look at the HSE_bandstructure_with_wannier90.sh.
Standard DFT run
Just as before
- INCAR (see INCAR.dft)
ISMEAR = 0 SIGMA = 0.01 NBANDS = 8
- KPOINTS (see KPOINST.6)
6x6x6 0 G 6 6 6 0 0 0
Increase the number of states to 24
This step is optional.
- INCAR (see INCAR.diag)
ISMEAR = 0 SIGMA = 0.01 ALGO = Exact NELM = 1 NBANDS = 24
HSE + LWANNIER90 run
Run the hybrid functional calculation and call wannier90 (see LWANNIER90_RUN). .
- INCAR (see INCAR.hse_with_wannier90)
ISMEAR = 0 SIGMA = 0.01 LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; AEXX = 0.25 ALGO = D ; TIME = 0.4 ; LDIAG = .TRUE. NKRED = 2 EDIFF = 1.E-6 NBANDS = 24 LWANNIER90_RUN = .TRUE.
You will have to provide some instructions for wannier90 as well:
- wannier90.win (see wannier90.win_start)
num_wann=18 num_bands=24 Begin Projections Si:s ; p ; d End Projections #dis_froz_max=9 dis_num_iter=100 #guiding_centres=true bands_plot = true begin kpoint_path L 0.50000 0.50000 0.5000 G 0.00000 0.00000 0.0000 G 0.00000 0.00000 0.0000 X 0.50000 0.00000 0.5000 X 0.50000 0.00000 0.5000 K 0.37500 -0.37500 0.0000 K 0.37500 -0.37500 0.0000 G 0.00000 0.00000 0.0000 end kpoint_path bands_num_points 40 bands_plot_format gnuplot xmgrace
Mind: If the wannier90.win file does not exist VASP will create a default wannier90.win compatible with
the POSCAR and INCAR files, which needs to be suitably modified by including the proper instruction required
to generate the maximally localized wannier functions (refer to the WANNIER90 manual).
Plot bandstructure (Wannier interpolation) using XMGRACE or GNUPLOT
If all went well, wannier90 will have generated the following bandstructure files which can be visualized using xmgrace or gnuplot:
- wannier90_band.agr
xmgrace ./wannier90_band.agr
- wannier90_band.dat
- wannier90_band.gnu
gnuplot -persist ./wannier90_band.gnu
- N.B.: Most modern versions of gnuplot will respond with an error message unless you remove the first line of wannier90_band.gnu (some deprecated syntax issue).