Bandgap of Si using different DFT+HF methods
Description: Bandgap of Si using different DFT+HF schemes (PBE, B3LYP, PBE0, HSE06, and HF)
- INCAR
## Better preconverge with PBE first ## and use the WAVECAR file as inout for the DFT+HF calculation ## Selects the B3LYP hybrid function #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 function #LHFCALC = .TRUE. ; #ALGO = D ; TIME = 0.4 ## Selects the HSE06 hybrid function #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 4 4 4 0 0 0
- 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
- script to extract eigenvalues and calculate the bandgap
grep " 4 " OUTCAR | head -8 | \
awk 'BEGIN{i=1}{a[i]=$2 ; i=i+1} END{for (j=1;j<i;j++) print j,a[j]}' > vband.dat
grep " 5 " OUTCAR | head -8 | \
awk 'BEGIN{i=1}{a[i]=$2 ; i=i+1} END{for (j=1;j<i;j++) print j,a[j]}' > cband.dat
- 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)
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