New Excitation at the Interface between High-Temperature Superconductors and Topological Insulators

There has been an increased interest in the interplay between d-wave superconducting order parameter and helical surface states of a topological insulator, due to the recent theoretical proposals predicting the emergence of novel excitations at these interfaces. Motivated by these intriguing proposals, we fabricated high-temperature superconductor/topological insulator junctions by the mechanical bonding method [1]. We report the observation of a zero-bias conductance peak (ZBCP) at temperatures below the critical temperature of the bulk superconductor. The ZBCP in our data indicates the emergence of a new excitation in our devices. I will present a detailed study of the differential conductance measurement of our samples at various temperatures and magnetic fields.\\[4pt] [1] P. Zareapour, et al., Nature Communications 3, 1056 (2012).