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Electron poor materials research group Group meeting Dec 2, 2010 Theory- VASP simple GW calculations on Si and GaAs

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Perform a static calculation on the target structure. Take the WAVECAR WAVEDER and CHGCAR from the static calculation and then execute the GW calculation. These runs were done on saguaro using 16 processors. KPOINT grid: 6X6X6 gamma Number of Bands: 150

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System = Si SIGMA = 0.01 #RECOMMENDED MINIMUM SETUP PREC = NORMAL #PRECISION ENCUT = 320 #LREAL =.FALSE. #.FALSE. MEANS USE RECIPROCAL LATTICE ISMEAR = 0 #USE GAUSSIAN SMEARING LOPTICS =.TRUE. NBANDS = 150

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System = GaAs SIGMA = 0.01 #RECOMMENDED MINIMUM SETUP PREC = NORMAL #PRECISION ENCUT = 320 #LREAL =.FALSE. #.FALSE. MEANS USE RECIPROCAL LATTICE ISMEAR = 0 #USE GAUSSIAN SMEARING LOPTICS =.TRUE. NBANDS = 150 ALGO = GW0 NOMEGA = 64 NELM = 4 PRECFOCK=N LSPECTRAL=.TRUE.

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GW run time: 68m6.3s The average difference between the valence and conduction band in the DFT is: 3.771 eV. Using GW the difference is 4.535 eV. ΔE=4.535 - 3.771 eV = 0.7644. The Si bandgap according to DFT is E g = 0.5797 eV. New Gap = ΔE + E g = 1.344 eV ??

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GW run time: 58m13.1s The average difference between the valence and conduction band in the DFT is: 3.750 eV. Using GW the difference is 4.514 eV. ΔE=4.514 - 3.750 eV = 0.7634. The GaAs bandgap according to DFT is E g = 0.6035 eV. New Gap = ΔE + E g = 1.367 eV ??

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