Bandstructure of SrVO3 in GW: Difference between revisions
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=== Bandstructure using WANNIER90 === | === Bandstructure using WANNIER90 === | ||
Add the following line to your {{FILE|INCAR}}: | |||
<pre> | |||
LWANNIER90_RUN = .TRUE. | |||
</pre> | |||
and restart VASP. | |||
== Obtain DFT virtual orbitals == | == Obtain DFT virtual orbitals == | ||
Revision as of 10:38, 12 September 2012
Description: the GW bandstructure of SrVO3 using VASP and WANNIER90.
Performing a GW calculation with VASP is a 3-step procedure: a DFT groundstate calculation, a calculation to obtain a number of virtual orbitals, and the actual GW calculation itself. In this example we will also see how the results of the GW calculation may be postprocessed with WANNIER90 to obtain the dispersion of the bands along the usual high symmetry directions in reciprocal space.
The DFT groundstate calculation
Everthing starts with a conventional DFT (in this LDA) groundstate calculation:
- INCAR.DFT
System = SrVO3 ISMEAR = -5 EMIN = -20 ; EMAX = 20 ; NEDOS = 1000 # usefull energy range for density of states EDIFF = 1E-8 # high precision for groundstate calculation KPAR = 3
Copy the aforementioned file to INCAR:
cp INCAR.DFT INCAR
- KPOINTS
Automatically generated mesh
0
Gamma
4 4 4
Mind: this is definitely not dense enough for a high-quality description of SrVO3, but in the interest of speed we will live with it.
- POSCAR
SrVO3 3.77706 #taken from 9x9x9 with sigma=0.2 ismear=2 +1.0000000000 +0.0000000000 +0.0000000000 +0.0000000000 +1.0000000000 +0.0000000000 +0.0000000000 +0.0000000000 +1.0000000000 Sr V O 1 1 3 Direct +0.0000000000 +0.0000000000 +0.0000000000 +0.5000000000 +0.5000000000 +0.5000000000 +0.5000000000 +0.5000000000 +0.0000000000 +0.5000000000 +0.0000000000 +0.5000000000 +0.0000000000 +0.5000000000 +0.5000000000
Analysis of the DOS
Bandstructure using WANNIER90
Add the following line to your INCAR:
LWANNIER90_RUN = .TRUE.
and restart VASP.
Obtain DFT virtual orbitals
- INCAR.DFT.all
System = SrVO3 ISMEAR = -5 EMIN = -20 ; EMAX = 20 ; NEDOS = 1000 # usefull energy range for density of states ALGO = Exact ; NELM = 1 # exact diagonalization one step suffices EDIFF = 1E-8 # high precision for groundstate calculation NBANDS = 96 # need for a lot of bands in GW LOPTICS = .TRUE. # we need d phi/ d k for GW calculations KPAR = 3
Copy the aforementioned file to INCAR:
cp INCAR.DFT.all INCAR
The GW calculation
- INCAR.GW0
System = SrVO3 ISMEAR = -5 EMIN = -20 ; EMAX = 20 ; NEDOS = 1000 # usefull energy range for density of states NBANDS = 96 # need for a lot of bands in GW ALGO = GW0 # NELM = 1 # one step so this is really G0W0 PRECFOCK = Fast # select fast mode for FFT's ENCUTGW = 100 # energy cutoff for response function NOMEGA = 200 # metal, we need a lot of frequency points MAXMEM = 2500 # memory per core NKRED = 2 # sample down the GW to a coarse 2x2x2 grid KPAR = 3
Copy the aforementioned file to INCAR:
cp INCAR.GW0 INCAR
Analysis of the DOS
Bandstructure using WANNIER90
Download
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