Conductance Oscillations in a Topological Insulator-Disordered Superconductor Hybrid Interface

TL;DR

This study demonstrates proximity-induced superconductivity in a topological insulator coupled with a disordered superconductor, revealing oscillations and conductance peaks influenced by topological surface states and superconducting fluctuations.

Contribution

It provides new insights into how topological surface states affect superconductivity in disordered superconductor-topological insulator hybrids.

Findings

Superconducting signatures observed at low temperatures despite InO being insulating.

Nearly periodic conductance oscillations at higher bias.

Disappearance of effects above the critical temperature T*.

Abstract

We report on the observation on proximity-induced superconductivity in the topological insulator BiSbTeSe2 coupled to a disordered superconductor, amorphous indium oxide (a-InO). Resistance temperature measurements reveal superconducting signatures at low temperatures, even when InO is in an insulating state, indicating the persistence of superconducting correlations. Differential conductance spectra reveal nearly periodic oscillations at higher bias, together with a pronounced zero-bias conductance peak. Both effect disappears at high temperature, marking the critical temperature (T*) of the superconducting islands in InO. These results underscore the influence of topological surface states on proximity-induced superconductivity and highlight the role of superconducting fluctuations in disordered superconductor/topological-insulator hybrid interfaces.