Conductance Oscillations in Gated Topological Insulator Heterostructures

Recent theoretical studies have shown that the properties of the surface state of 3D Topological Insulators (TIs) may be different from the topological interface states in a heterostructure containing TIs [1]. Directly accessing these interface states is, however, challenging. We propose that a transport measurement on a gated double junction sandwich device yields critical information about the topological interface states. We show that the conductance oscillations as a function of the gating potential can be used to extract the Fermi velocity and other parameters characterizing their dispersion. Crucially, these results are only weakly dependent on the boundary conditions at the lateral sandwich junctions. We discuss relevance of our results to proposed applications of TIs in functional devices.

[1] Mahmoud M. Asmar, Daniel E. Sheehy and Ilya Vekhter, PRB 95 241115 (2017).