Bandgap of Si using different DFT+HF methods: Difference between revisions
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{{Template:Hybrid_functionals - Tutorial}} | |||
== Task == | |||
Calculation of the band gap in Si using different DFT+HF schemes [[list_of_hybrid_functionals|(PBE, B3LYP, PBE0, HSE06, and HF)]]. | |||
== Input == | |||
=== {{TAG|POSCAR}} === | |||
<pre> | |||
System: Si | |||
5.430 | |||
0.5 0.5 0.0 | |||
0.0 0.5 0.5 | |||
0.5 0.0 0.5 | |||
1 | |||
Cartesian | |||
0 0 0 | |||
0.25 0.25 0.25 | |||
</pre> | |||
=== {{TAG|INCAR}} === | |||
## Better preconverge with PBE first | |||
## and use the WAVECAR file as inout for the DFT+HF calculation | |||
## Selects the B3LYP hybrid functional | |||
#{{TAGBL|LHFCALC}} = .TRUE. ; {{TAGBL|GGA}} = B3 ; {{TAGBL|AEXX}} = 0.2 ; {{TAGBL|AGGAX}} = 0.72 | |||
#{{TAGBL|AGGAC}} = 0.81 ; {{TAGBL|ALDAC}} = 0.19 | |||
#{{TAGBL|ALGO}} = D ; {{TAGBL|TIME}} = 0.4 | |||
## Selects the PBE0 hybrid functional | |||
#{{TAGBL|LHFCALC}} = .TRUE. ; | |||
#{{TAGBL|ALGO}} = D ; {{TAGBL|TIME}} = 0.4 | |||
## Selects the HSE06 hybrid functional | |||
#{{TAGBL|LHFCALC}} = .TRUE. ; {{TAGBL|HFSCREEN}} = 0.2 ; | |||
#{{TAGBL|ALGO}} = D ; {{TAGBL|TIME}} = 0.4 | |||
## Selects HF | |||
#{{TAGBL|LHFCALC}} = .TRUE. ; {{TAGBL|AEXX}} = 1.0 ; {{TAGBL|ALDAC}} = 0.0 ; {{TAGBL|AGGAC}} = 0 | |||
#{{TAGBL|ALGO}} = D ; {{TAGBL|TIME}} = 0.4 | |||
## Leave this in | |||
{{TAGBL|ISMEAR}} = 0 | |||
{{TAGBL|SIGMA}} = 0.01 | |||
{{TAGBL|GGA}} = PE | |||
=== {{TAG|KPOINTS}} === | |||
<pre> | <pre> | ||
k-points | k-points | ||
| Line 41: | Line 57: | ||
</pre> | </pre> | ||
=== Calculation === | |||
*script to extract eigenvalues and calculate the bandgap | *script to extract eigenvalues and calculate the bandgap | ||
| Line 81: | Line 86: | ||
</pre> | </pre> | ||
== | == Download == | ||
[[Media:Si hybrids gap.tgz| Si_hybrids_gap.tgz]] | |||
{{Template:Hybrid_functionals}} | |||
Back to the [[The_VASP_Manual|main page]]. | |||
[[Category:Examples]] | [[Category:Examples]] | ||
Latest revision as of 09:24, 6 April 2022
Overview > bandgap of Si using different DFT+HF methods > MgO optimum mixing > fcc Ni DOS with hybrid functional > Si bandstructure > List of tutorials
Task
Calculation of the band gap in Si using different DFT+HF schemes (PBE, B3LYP, PBE0, HSE06, and HF).
Input
POSCAR
System: Si 5.430 0.5 0.5 0.0 0.0 0.5 0.5 0.5 0.0 0.5 1 Cartesian 0 0 0 0.25 0.25 0.25
INCAR
## Better preconverge with PBE first ## and use the WAVECAR file as inout for the DFT+HF calculation ## Selects the B3LYP hybrid functional #LHFCALC = .TRUE. ; GGA = B3 ; AEXX = 0.2 ; AGGAX = 0.72 #AGGAC = 0.81 ; ALDAC = 0.19 #ALGO = D ; TIME = 0.4 ## Selects the PBE0 hybrid functional #LHFCALC = .TRUE. ; #ALGO = D ; TIME = 0.4 ## Selects the HSE06 hybrid functional #LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; #ALGO = D ; TIME = 0.4 ## Selects HF #LHFCALC = .TRUE. ; AEXX = 1.0 ; ALDAC = 0.0 ; AGGAC = 0 #ALGO = D ; TIME = 0.4 ## Leave this in ISMEAR = 0 SIGMA = 0.01 GGA = PE
KPOINTS
k-points 0 Gamma 6 6 6 0 0 0
Calculation
- script to extract eigenvalues and calculate the bandgap
homo=`awk '/NELECT/ {print $3/2}' $1`
lumo=`awk '/NELECT/ {print $3/2+1}' $1`
nkpt=`awk '/NKPTS/ {print $4}' $1`
e1=`grep " $homo " $1 | head -$nkpt | sort -n -k 2 | tail -1 | awk '{print $2}'`
e2=`grep " $lumo " $1 | head -$nkpt | sort -n -k 2 | head -1 | awk '{print $2}'`
echo "HOMO: band:" $homo " E=" $e1
echo "LUMO: band:" $lumo " E=" $e2
- type
./gap.sh OUTCAR
- README.txt
For each HF+DFT method (B3LYP, PBE0, HSE06, and HF) compute the bandgap of Si
adopting the following procedure:
i) Perform a standard PBE calculation
ii) Perform a HF+DFT run (VASP reads in the WAVECAR from run (i)
iii) Calculate the value of the bandgap by running the script 'gap':
bandgap = min(cband) - max(vband)
Download
Overview > bandgap of Si using different DFT+HF methods > MgO optimum mixing > fcc Ni DOS with hybrid functional > Si bandstructure > List of tutorials
Back to the main page.