Polar discontinuities and interfacial electronic properties of Bi${}_2$O${}_2$Se on SrTiO${}_3$

Abstract

The layered oxychalcogenide semiconductor Bi${}_2$O${}_2$Se (BOS) hosts a multitude of unusual properties including high electron mobility. Owing to similar crystal symmetry and lattice constants, the perovskite oxide SrTiO${}_3$ (STO) has been demonstrated to be an excellent substrate for wafer-scale growth of atomically thin BOS films. However, the structural and electronic properties of the BOS/STO interface remain poorly understood. Here, through first-principles study, we reveal that polar discontinuities and interfacial contact configurations have a strong impact on the electronic properties of ideal BOS/STO interfaces. The lowest-energy [Bi-TiO${}_2$] contact type, which features the contact between a Bi${}_2$O${}_2$ layer of BOS with the TiO${}_2$-terminated surface of STO, incurs significant interfacial charge transfer from BOS to STO, producing a BOS/STO-mixed, $n$-type metallic state at the interface. By contrast, the [Se-SrO] contact type, which is the most stable contact configuration between BOS and SrO-terminated STO substrate, has a much smaller interfacial charge transfer from STO to BOS and exhibits $p$-type electronic structure with much weaker interfacial hybridization between BOS and STO. These results indicate that BOS grown on TiO${}_2$-terminated STO substrates could be a fruitful system for exploring emergent phenomena at the interface between an oxychalcogenide and an oxide, whereas BOS grown on SrO-terminated substrates may be more advantageous for preserving the excellent intrinsic transport properties of BOS.

9 pages, 4 figures

References in corpus (3)

• Are we van der Waals ready?
• Giant modulation of the electron mobility in semiconductor Bi${}_2$O${}_2$Se via incipient ferroelectric phase transition
• Huge permittivity and premature metallicity in Bi${}_2$O${}_2$Se single crystals

Cited by in corpus (1)

• Highly Polarizable Semiconductors and Universal Origin of Ferroelectricity in Materials with a Litharge-Type Structural Unit