Linear magneto-resistance in topological crystalline insulator PbTe/SnTe heterostructure: van der Pauw vs. Corbino measurements

Non-saturating linear magneto-resistance (MR) effect is a novel magneto-transport phenomenon widely observed in various topological materials with gapless dispersion. Despite its ubiquitous presence in graphene, topological insulators, topological crystalline insulators, Dirac semimetals, and Weyl semimetals, the origin of the large linear MR effect has not been clearly resolved. The two leading theories explaining the linear MR effect are the quantum linear MR model (by Abrikosov) and the mobility fluctuation induced classical linear MR model (by Littlewood and Parish). Here, we report a magneto-transport study on heterostructures of topological crystalline insulator(TCI) SnTe and trivial insulator PbTe and elucidate the linear MR effect in TCI SnTe by comparing the MR measurement in the standard van der Pauw geometry vs. the Corbino geometry where the longitudinal magneto-conductivity σ_xx(B) is directly measured. Our results revealed consistency between the two geometries and show that the Drude model clearly fails to account for the magneto-conductivity data. We will then discuss the implications of our data in the two leading models of linear MR.