Self-consistent GW calculations for semiconductors and insulators

Author(s)
M Shishkin, Georg Kresse
Abstract

We present GW calculations for small and large gap systems comprising typical semiconductors (Si, SiC, GaAs, GaN, ZnO, ZnS, CdS, and AlP), small gap semiconductors (PbS, PbSe, and PbTe), insulators (C, BN, MgO, and LiF), and noble gas solids (Ar and Ne). It is shown that the G0 W0 approximation always yields too small band gaps. To improve agreement with experiment, the eigenvalues in the Green's function G (G W0) and in the Green's function and the dielectric matrix (GW) are updated until self-consistency is reached. The first approximation leads to excellent agreement with experiment, whereas an update of the eigenvalues in G and W gives too large band gaps for virtually all materials. From a pragmatic point of view, the G W0 approximation thus seems to be an accurate and still reasonably fast method for predicting quasiparticle energies in simple sp -bonded systems. We furthermore observe that the band gaps in materials with shallow d states (GaAs, GaN, and ZnO) are systematically underestimated. We propose that an inaccurate description of the static dielectric properties of these materials is responsible for the underestimation of the band gaps in G W0, which is itself a result of the incomplete cancellation of the Hartree self-energy within the d shell by local or gradient corrected density functionals. © 2007 The American Physical Society.

Organisation(s)
Computational Materials Physics
Journal
Physical Review B
Volume
75
No. of pages
9
ISSN
1098-0121
DOI
https://doi.org/10.1103/PhysRevB.75.235102
Publication date
2007
Peer reviewed
Yes
Austrian Fields of Science 2012
103015 Condensed matter
Portal url
https://ucrisportal.univie.ac.at/en/publications/a002b26f-a664-4924-8897-06c9e64d2424