Theoretical unification of hybrid-DFT and DFT+U methods for the treatment of localized orbitals

Viktor Ivády, Rickard Armiento, Krisztián Szász, Erik Janzén, Adam Gali, Igor A. Abrikosov

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Hybrid functionals serve as a powerful practical tool in different fields of computational physics and quantum chemistry. On the other hand, their applicability for the case of correlated d and f orbitals is still questionable and needs more considerations. In this article we formulate the on-site occupation dependent exchange correlation energy and effective potential of hybrid functionals for localized states and connect them to the on-site correction term of the DFT+U method. The resultant formula indicates that the screening of the onsite electron repulsion is governed by the ratio of the exact exchange in hybrid functionals. Our derivation provides a theoretical justification for adding a DFT+U-like on-site potential in hybrid-DFT calculations to resolve issues caused by overscreening of localized states. The resulting scheme, hybrid DFT+Vw, is tested for chromium impurity in wurtzite AlN and vanadium impurity in 4H-SiC, which are paradigm examples of systems with different degrees of localization between host and impurity orbitals.

Original languageEnglish
Article number035146
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume90
Issue number3
DOIs
Publication statusPublished - Jul 30 2014

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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