Oral: Electronic Transport Studies of Surface and Bulk States in Correlated Insulators: A Comparative Study of CrSb₂ and Related Materials.

There is growing evidence suggesting that many of the correlated insulators have a conducting surface originating from a non-trivial band topology. A recent study found the existence of a conducting surface in CrSb₂ using thickness-dependent transport but claimed the origin is trivial (non-topological) based on the absence of band inversion in first-principles calculations and the bands observed in ARPES [1]. In our own effort, we investigate electronic transport using the inverted resistance technique. This method not only reveals the surface states but quantifies the conductivities of the two channels distinctively. We compare our transport measurement with the previous reports of CrSb₂ [1] and other correlated insulators that host surface states (SmB₆, FeSi, and FeSb₂). In addition to our efforts to find evidence of non-trivial topology in CrSb₂, we report the important transport quantities such as the bulk activation energy, the surface carrier density, and the surface mobility. Additionally, we will briefly discuss our recent efforts in identifying new surface states and robust insulating bulk in other correlated insulators.

[1] Qianheng Du et al. Phys. Rev. Research 2, 043085 (2020)