Journal article · Preprint article
Quasiparticle GW calculations for solids, molecules, and two-dimensional materials
We present a plane-wave implementation of the GW approximation within the projector augmented wave method code GPAW. The computed band gaps of ten bulk semiconductors and insulators deviate on average by 0.2eV (~5%) from the experimental values, the only exception being ZnO where the calculated band gap is around 1eV too low.
Similar relative deviations are found for the ionization potentials of a test set of 32 small molecules. The importance of substrate screening for a correct description of quasiparticle energies and Fermi velocities in supported two-dimensional (2D) materials is illustrated by the case of graphene/h-BN interfaces.
Due to the long-range Coulomb interaction between periodically repeated images, the use of a truncated interaction is found to be essential for obtaining converged results for 2D materials. For all systems studied, a plasmon-pole approximation is found to reproduce the full frequency results to within 0.2eV with a significant gain in computational speed.
Throughout, we compare the GW results with different exact exchange-based approximations. For completeness, we provide a mathematically rigorous and physically transparent introduction to the notion of quasiparticle states.
Language: | English |
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Year: | 2013 |
Pages: | 15 |
ISSN: | 1550235x and 10980121 |
Types: | Journal article and Preprint article |
DOI: | 10.1103/PhysRevB.87.235132 |
ORCIDs: | Hüser, Falco , Olsen, Thomas and Thygesen, Kristian Sommer |