Surface magnetotransport in the topological Kondo insulator candidate FeSb₂

Topological Kondo insulators (TKIs) are a class of materials where strong electron correlations from localized electrons, combined with spin-orbit coupling, lead to the emergence of topologically protected surface states. Several candidate materials are known for TKIs, with SmB₆ being a representative example.

FeSb₂ is a narrow-gap semiconductor that has recently emerged as a potential TKI [1]. In this study, we explore its surface transport properties to explore its topological nature. Low-temperature resistivity measurements reveal that metallic surface conduction dominates over the insulating bulk. We then conducted a comprehensive analysis of the magnetotransport properties of these metallic surface states, including current dependence, angle dependence, and nonreciprocity. In this presentation, we will discuss the distinctive results from these measurements, which differentiate this material from normal topological insulators.

[1] Xu, Ke-Jun, et al. Proc. Natl. Acad. Sci. 117, 15409 (2020).