Higher order topological insulators host helical, one-dimensional (1D) edge modes along its hinges that are protected by crystal and time-reversal symmetry (1). Proximity induced superconductivity on these hinge states is predicted to be topological in nature and provide a platform for realization of Majorana zero modes. Previously, scanning tunneling microscopy (STM) studies have found evidence for the presence of these particular edge states on the surface of bulk Bismuth(111) (2).

By epitaxial growth of Bismuth (Bi) thin films on the surface of Nb, we have successfully induced superconductivity into (111) oriented Bi films. Using high-resolution STM spectroscopy and quasi-particle interference mapping, we characterize the nature of both the normal and the superconducting properties of the Bi thin film. We find the hinge mode to develop a hard superconducting gap that appears to be spectroscopically distinct from the gap on the Bi surface. We will describe these and other experiments designed to elucidate the nature of superconductivity and search for signatures of Majorana zero modes in the hinge states of Bi.