Kohn-Sham band gaps and potentials of solids from the optimised effective potential method within the random phase approximation

Author(s)
Jiri Klimes, Georg Kresse
Abstract

We present an implementation of the optimised effective potential (OEP) scheme for the exact-exchange (EXX) and random phase approximation (RPA) energy functionals and apply these methods to a range of bulk materials. We calculate the Kohn-Sham (KS) potentials and the corresponding band gaps and compare them to the potentials obtained by standard local density approximation (LDA) calculations. The KS gaps increase upon going from the LDA to the OEP in the RPA and finally to the OEP for EXX. This can be explained by the different depth of the potentials in the bonding and interstitial regions. To obtain the true quasi-particle gaps the derivative discontinuities or G 0 W 0 corrections need to be added to the RPA-OEP KS gaps. The predicted G 0 W 0@RPA-OEP quasi-particle gaps are about 5% too large compared to the experimental values. However, compared to G 0 W 0 calculations based on local or semi-local functionals, where the errors vary between different materials, we obtain a rather consistent description among all the materials.

Organisation(s)
Computational Materials Physics
Journal
Journal of Chemical Physics
Volume
140
No. of pages
13
ISSN
0021-9606
DOI
https://doi.org/10.1063/1.4863502
Publication date
02-2014
Peer reviewed
Yes
Austrian Fields of Science 2012
103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/kohnsham-band-gaps-and-potentials-of-solids-from-the-optimised-effective-potential-method-within-the-random-phase-approximation(a76a2dd6-3469-4717-b6a6-ef6418d5ae8d).html