Bandgap of Si in GW
Description: calculation of the bandgap of Si using various flavours of 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
ISMEAR = 0 SIGMA = 0.05 GGA = PE
- KPOINTS
6x6x6 0 G 6 6 6 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 2 cart 0.00 0.00 0.00 0.25 0.25 0.25
Step: obtain DFT virtual orbitals
- INCAR
ALGO = Exact NBANDS = 64 LOPTICS = .TRUE. ; CSHIFT = 0.1 NEDOS = 2000 ## you might try #LPEAD = .TRUE. </prec> To quickly find the QP-energy of the highest lying occupied state, try grep " 4 " OUTCAR | sort -n -k 3 | tail -1 | awk '{print $3}' and for the lowest lying unoccupied state, grep " 5 " OUTCAR | sort -n -k 3 | head -1 | awk '{print $3}'Download
Si_bandgap_GW.tgz
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