Macroscopic Quantum Tunneling in Superconducting Junctions of beta-Ag2Se Topological Insulator Nanowire

Abstract

We report on the fabrication and electrical transport properties of superconducting junctions made of beta-Ag2Se topological insulator (Tl) nanowires in contact with Al superconducting electrodes. The temperature dependence of the critical current indicates that the superconducting junction belongs to a short and diffusive junction regime. As a characteristic feature of the narrow junction, the critical current decreases monotonously with increasing magnetic field. The stochastic distribution of the switching current exhibits the macroscopic quantum tunneling behavior, which is robust up to T = 0.8 K. Our observations indicate that the Tl nanowire-based Josephson junctions can be a promising building block for the development of nanohybrid superconducting quantum bits.