Band-gap trend of corundum oxides α - <i>M</i><sub>2</sub>O<sub>3</sub> (<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://ucris.univie.ac.at/portal/en/publications/bandgap-trend-of-corundum-oxides---m2o3-m--co-rh-ir-an-ab-initio-study(66708f43-8636-4845-a2bb-68130d830ea4).html