Bandgap of Si in GW: Difference between revisions
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=== Step: obtain DFT virtual orbitals === | === Step: obtain DFT virtual orbitals === | ||
*INCAR | |||
<pre> | |||
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 | To quickly find the QP-energy of the highest lying occupied state, try | ||
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grep " 5 " OUTCAR | sort -n -k 3 | head -1 | awk '{print $3}' | grep " 5 " OUTCAR | sort -n -k 3 | head -1 | awk '{print $3}' | ||
== Download == | == Download == | ||
Revision as of 16:00, 7 June 2012
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
To the list of examples or to the main page