Signature of band inversion in the perovskite thin-film alloys $\mathrm{BaS}{\mathrm{n}}_{1--x}\mathrm{P}{\mathrm{b}}_{x}{\mathrm{O}}_{3}$

Signature of band inversion in the perovskite thin-film alloys $BaS n_{1 - x} P b_{x} O_{3}$

Junichi Shiogai, Takumaru Chida, Kenichiro Hashimoto, Kohei Fujiwara, Takahiko Sasaki, and Atsushi Tsukazaki

Phys. Rev. B 101, 125125 – Published 25 March 2020

Abstract

Perovskite oxides $A B O_{3}$ containing heavy B-site elements are a class of candidate materials to host topological metals with a large spin-orbit interaction. In contrast to the band insulator $BaSn O_{3}$ , the semimetal $BaPb O_{3}$ is proposed to be a typical example with an inverted band structure, the conduction band of which is composed of mainly the $O − 2 p$ orbital. In this paper, we exemplify a band-gap modification by systematic structural, optical, and transport measurements in $BaS n_{1 - x} P b_{x} O_{3}$ films. A sudden suppression of the conductivity and an enhancement of the weak antilocalization effect at $x = 0.9$ indicate the presence of a singular point in the electronic structure as a signature of the band inversion. Our findings provide an intriguing platform for combining topological aspects and electron correlation in perovskite oxides based on band-gap engineering.