Band-gap trend of corundum oxides α - <i>M</i>₂O₃ (<i>M</i> = Co, Rh, Ir): An ab initio study

Author(s)

Xuefen Cai, Su Huai Wei, Peter Deák, Cesare Franchini, Shu Shen Li, Hui Xiong Deng

Abstract

In recent years, d6 transition-metal corundum oxides α-M2O3 (M=Co, Rh, Ir) have garnered significant interest due to their notable p-type conductivity; however, their electronic properties remain controversial. In this study, we employ first-principles calculations within different functional levels to systematically investigate the geometry and electronic structure of α-M2O3. Our findings reveal that these oxides have a relatively small difference between the indirect and direct band gap, contradicting previous studies. Additionally, we demonstrate that the band gaps of these oxides are closely associated with the ligand field splitting of the cation M d orbitals and the experimentally observed nonmonotonic trend of the direct band-gap variation can be explained by the orbital-dependent Coulomb and exchange interactions. This study enhances our understanding of how the involvement of d orbitals impacts the band gap of transition-metal oxides.

Organisation(s)

Computational Materials Physics

External organisation(s)

Beijing Computational Science Research Center, University of Bologna, Chinese Academy of Sciences (CAS)

Journal

Physical Review B

Volume

108

No. of pages

6

ISSN

2469-9950

DOI

https://doi.org/10.1103/PhysRevB.108.075137

Publication date

08-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

103015 Condensed matter, 103043 Computational physics

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, Condensed Matter Physics

Portal url

https://ucrisportal.univie.ac.at/en/publications/66708f43-8636-4845-a2bb-68130d830ea4