Bandstructure of Si in GW (VASP2WANNIER90): Difference between revisions

Latest revision as of 12:41, 3 June 2024

Overview > bandgap of Si in GW > bandstructure of Si in GW (VASP2WANNIER90) > bandstructure of SrVO3 in GW > CRPA of SrVO3 > Equilibrium volume of Si in the RPA > List of tutorials

Task

Calculation of the bandstructure of Si in GW using the VASP2WANNIER90 interface.

Mind: The procedure to compute bandstructure in GW using V2W is almost identical to the corresponding HSE one described in Si bandstructure.

Mind: The standard procedure for GW calculations is described in Bandgap of Si in GW.

Step 1: a DFT groundstate calculation

Everything starts with a standard DFT groundstate calculation (in this case PBE).

INCAR

ISMEAR =  0
SIGMA  =  0.05
GGA    = PE

KPOINTS

POSCAR

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

Step 2: obtain DFT virtual orbitals

To obtain a WAVECAR file with a reasonable number of virtual orbitals (50-100 per atom) we need to restart from the previous groundstate calculation with ALGO=Exact, and manually set the number of bands by means of the NBANDS-tag. To obtain the corresponding WAVEDER file we additionally specify LOPTICS=.TRUE.

INCAR

ALGO = Exact
NBANDS  = 64
LOPTICS = .TRUE.
NEDOS = 2000
    
ISMEAR =  0
SIGMA  =  0.05
GGA    = PE

Step 3: GW calculation including LWANNIER90 TAG

Restart from the WAVECAR and WAVEDER files of the previous calculation, with

INCAR

## Frequency dependent dielectric tensor including
## local field effects within the RPA (default) or
## including changes in the DFT xc-potential (LRPA=.FALSE.).
## N.B.: beware one first has to have done a
## calculation with ALGO=Exact and LOPTICS=.TRUE.
## and a reasonable number of virtual states (see above)
ALGO = GW0 ; LSPECTRAL = .TRUE. ; NOMEGA = 50
#LRPA = .FALSE. 
## be sure to take the same number of bands as for
## the LOPTICS=.TRUE. calculation, otherwise the
## WAVEDER file is not read correctly
NBANDS = 64
##VASP2WANNIER90
LWANNIER90=.TRUE.

Use the wannier90.win file given below which contains all instructions needed to generate the necessary input files for the WANNIER90 runs (wannier90.amn, wannier90.mmn, wannier90.eig).

wannier90.win

num_wann=8
num_bands=8

exclude_bands = 9-64

Begin Projections
Si:sp3
End Projections

dis_froz_max=9
dis_num_iter=1000

guiding_centres=true

# Bandstructure plot 
#restart         =  plot
#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

begin unit_cell_cart
     2.7150000     2.7150000     0.0000000
     0.0000000     2.7150000     2.7150000
     2.7150000     0.0000000     2.7150000
end unit_cell_cart

begin atoms_cart
Si       0.0000000     0.0000000     0.0000000
Si       1.3575000     1.3575000     1.3575000
end atoms_cart

mp_grid =     4     4     4

begin kpoints
     0.0000000     0.0000000     0.0000000
     0.2500000     0.0000000     0.0000000
     0.5000000     0.0000000     0.0000000
     0.2500000     0.2500000     0.0000000
     0.5000000     0.2500000     0.0000000
    -0.2500000     0.2500000     0.0000000
     0.5000000     0.5000000     0.0000000
    -0.2500000     0.5000000     0.2500000
     0.0000000     0.2500000     0.0000000
     0.0000000     0.0000000     0.2500000
    -0.2500000    -0.2500000    -0.2500000
    -0.2500000     0.0000000     0.0000000
     0.0000000    -0.2500000     0.0000000
     0.0000000     0.0000000    -0.2500000
     0.2500000     0.2500000     0.2500000
     0.0000000     0.5000000     0.0000000
     0.0000000     0.0000000     0.5000000
    -0.5000000    -0.5000000    -0.5000000
     0.0000000     0.2500000     0.2500000
     0.2500000     0.0000000     0.2500000
    -0.2500000    -0.2500000     0.0000000
    -0.2500000     0.0000000    -0.2500000
     0.0000000    -0.2500000    -0.2500000
     0.0000000     0.5000000     0.2500000
     0.2500000     0.0000000     0.5000000
    -0.2500000    -0.2500000     0.2500000
    -0.5000000    -0.2500000    -0.5000000
     0.2500000     0.5000000     0.0000000
     0.2500000    -0.2500000    -0.2500000
    -0.5000000    -0.5000000    -0.2500000
     0.0000000     0.2500000     0.5000000
    -0.2500000     0.2500000    -0.2500000
    -0.2500000    -0.5000000    -0.5000000
     0.5000000     0.0000000     0.2500000
    -0.5000000    -0.2500000     0.0000000
     0.0000000    -0.5000000    -0.2500000
    -0.2500000     0.0000000    -0.5000000
     0.2500000     0.2500000    -0.2500000
     0.5000000     0.2500000     0.5000000
    -0.2500000    -0.5000000     0.0000000
    -0.2500000     0.2500000     0.2500000
     0.5000000     0.5000000     0.2500000
     0.0000000    -0.2500000    -0.5000000
     0.2500000    -0.2500000     0.2500000
     0.2500000     0.5000000     0.5000000
    -0.5000000     0.0000000    -0.2500000
     0.0000000    -0.2500000     0.2500000
     0.2500000     0.0000000    -0.2500000
    -0.2500000    -0.2500000    -0.5000000
     0.2500000     0.5000000     0.2500000
     0.2500000    -0.2500000     0.0000000
    -0.5000000    -0.2500000    -0.2500000
     0.2500000     0.2500000     0.5000000
     0.0000000     0.2500000    -0.2500000
    -0.2500000    -0.5000000    -0.2500000
     0.5000000     0.2500000     0.2500000
    -0.2500000     0.0000000     0.2500000
     0.0000000     0.5000000     0.5000000
     0.5000000     0.0000000     0.5000000
     0.2500000    -0.2500000     0.5000000
     0.5000000     0.2500000    -0.2500000
    -0.5000000    -0.2500000    -0.7500000
     0.2500000    -0.5000000    -0.2500000
    -0.2500000     0.2500000    -0.5000000
end kpoints

Step 4: WANNIER90

Compute Wannier functions

run wannier90:

wannier90.x wannier90

This run generates the wannier90 standard output (wannier90.wout) and the file wannier90.chk needed for the wannier interpolation (next step)

Obtain bandstructure (Wannier interpolation)

Uncomment the bandstructure plot flags in wannier90.win and rerun (restart) wannier90:

wannier90.x wannier90

This run generates the following bandstructure files which can be visualized using xmgrace or gnuplot:

wannier90_band.agr

wannier90_band.dat

wannier90_band.gnu

to plot the band structure using gnuplot: gnuplot -persist wannier90_band.gnu

Download

Si_bandstructure_GW.tgz

Overview > bandgap of Si in GW > bandstructure of Si in GW (VASP2WANNIER90) > bandstructure of SrVO3 in GW > CRPA of SrVO3 > Equilibrium volume of Si in the RPA > List of tutorials

Back to the main page.

@@ Line 1: / Line 1: @@
-Description: calculation of the bandstructure of Si in GW using the VASP2WANNIER90 interface.
+{{Template:GW - Tutorial}}
+== Task ==
+Calculation of the bandstructure of Si in GW using the VASP2WANNIER90 interface.
+----
 '''Mind''': The procedure to compute bandstructure in GW using V2W is almost identical to the corresponding HSE one
-described in [[VASP_example_calculations#Si_bandstructure|Si bandstructure]].
+described in [[Si_bandstructure|Si bandstructure]].
+'''Mind''': The standard procedure for GW calculations is described in
+[[Bandgap of Si in GW|Bandgap of Si in GW]].
 ----
-To do GW calculations we have to follow a 3-step procedure.
 == Step 1: a DFT groundstate calculation ==
 Everything starts with a standard DFT groundstate calculation (in this case PBE).
-*INCAR
+*{{TAG|INCAR}}
-<pre>
-ISMEAR =  0
+ {{TAGBL|ISMEAR}} =  0
-SIGMA  =  0.05
+ {{TAGBL|SIGMA}}  =  0.05
-GGA    = PE
+ {{TAGBL|GGA}}    = PE
-</pre>
-*KPOINTS
+*{{TAG|KPOINTS}}
 <pre>
 x4x4
@@ Line 26: / Line 32: @@
 </pre>
-*POSCAR
+*{{TAG|POSCAR}}
 <pre>
 system Si
@@ Line 45: / Line 51: @@
 To obtain the corresponding {{FILE|WAVEDER}} file we additionally specify {{TAG|LOPTICS}}=.TRUE.
-*INCAR
+*{{TAG|INCAR}}
-<pre>
-ALGO = Exact
-NBANDS  = 64
-LOPTICS = .TRUE.
-NEDOS = 2000
-ISMEAR =  0
-SIGMA  =  0.05
-GGA    = PE
-</pre>
+ {{TAGBL|ALGO}} = Exact
+ {{TAGBL|NBANDS}}  = 64
+ {{TAGBL|LOPTICS}} = .TRUE.
+ {{TAGBL|NEDOS}} = 2000
+ {{TAGBL|ISMEAR}} =  0
+ {{TAGBL|SIGMA}}  =  0.05
+ {{TAGBL|GGA}}    = PE
 == Step 3: GW calculation including LWANNIER90 TAG==
 Restart from the {{FILE|WAVECAR}} and {{FILE|WAVEDER}} files of the previous calculation, with
-*INCAR
+*{{TAG|INCAR}}
-<pre>
-## Frequency dependent dielectric tensor including
+ ## Frequency dependent dielectric tensor including
-## local field effects within the RPA (default) or
+ ## local field effects within the RPA (default) or
-## including changes in the DFT xc-potential (LRPA=.FALSE.).
+ ## including changes in the DFT xc-potential ({{TAGBL|LRPA}}=.FALSE.).
-## N.B.: beware one first has to have done a
+ ## N.B.: beware one first has to have done a
-## calculation with ALGO=Exact and LOPTICS=.TRUE.
+ ## calculation with {{TAGBL|ALGO}}=Exact and {{TAGBL|LOPTICS}}=.TRUE.
-## and a reasonable number of virtual states (see above)
+ ## and a reasonable number of virtual states (see above)
-ALGO = GW0 ; LSPECTRAL = .TRUE. ; NOMEGA = 50
+ {{TAGBL|ALGO}} = GW0 ; {{TAGBL|LSPECTRAL}} = .TRUE. ; {{TAGBL|NOMEGA}} = 50
-#LRPA = .FALSE.
+ #{{TAGBL|LRPA}} = .FALSE.
-## be sure to take the same number of bands as for
+ ## be sure to take the same number of bands as for
-## the LOPTICS=.TRUE. calculation, otherwise the
+ ## the {{TAGBL|LOPTICS}}=.TRUE. calculation, otherwise the
-## WAVEDER file is not read correctly
+ ## {{TAGBL|WAVEDER}} file is not read correctly
-NBANDS = 64
+ {{TAGBL|NBANDS}} = 64
-##VASP2WANNIER90
+ ##VASP2WANNIER90
-LWANNIER90=.TRUE.
+ {{TAGBL|LWANNIER90}}=.TRUE.
-</pre>
-Use the wannier90.win file given below which contains all instructions needed to calculate the
+Use the wannier90.win file given below which contains all instructions needed to generate the
-necessary input files for the WANNIER90 runs.
+necessary input files for the WANNIER90 runs (wannier90.amn, wannier90.mmn, wannier90.eig).
 *wannier90.win
@@ Line 87: / Line 90: @@
 num_bands=8
-exclude_bands 9-64
+exclude_bands = 9-64
 Begin Projections
@@ Line 191: / Line 194: @@
 </pre>
+== Step 4: WANNIER90==
+=== Compute Wannier functions ===
+run wannier90:
-== Step 4: WANNIER90==
+wannier90.x wannier90
+This run generates the wannier90 standard output (wannier90.wout)
+and the file wannier90.chk needed for the wannier interpolation (next step)
+=== Obtain bandstructure (Wannier interpolation) ===
+Uncomment the bandstructure plot flags in wannier90.win and rerun (restart) wannier90:
+wannier90.x wannier90
+This run generates the following bandstructure files which can be visualized using xmgrace or gnuplot:
+wannier90_band.agr
+wannier90_band.dat
+wannier90_band.gnu
+to plot the band structure using gnuplot:
+<code>gnuplot -persist wannier90_band.gnu</code>
 == Download ==
-[http://www.vasp.at/vasp-workshop/examples/Si_bandstructure_GW.tgz Si_bandstructure_GW.tgz]
+[[Media:Si bandstructure GW.tgz| Si_bandstructure_GW.tgz]]
-----
+{{Template:GW - Tutorial}}
-[[VASP_example_calculations|To the list of examples]] or to the [[The_VASP_Manual|main page]]
+Back to the [[The_VASP_Manual|main page]].
 [[Category:Examples]]