Self-consistent GW calculations for semiconductors and insulators

Autor(en)

M Shishkin, Georg Kresse

Abstrakt

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(en)

Computergestützte Materialphysik

Externe Organisation(en)

Universität Wien

Journal

Physical Review B

Band

75

Anzahl der Seiten

9

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.75.235102

Publikationsdatum

2007

Peer-reviewed

Ja

ÖFOS 2012

103015 Kondensierte Materie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/a002b26f-a664-4924-8897-06c9e64d2424