Quantum Hall Effect in a Josephson Junction

TL;DR

This paper reports on the fabrication and analysis of InAs/Nb Josephson junctions that exhibit supercurrent, high critical temperature, and quantum Hall effects, highlighting their potential for topological quantum devices.

Contribution

It introduces a new hybrid superconductor/semiconductor device platform with controllable supercurrent and quantum Hall states, enabling exploration of topological phenomena.

Findings

Demonstrated supercurrent flow with critical temperature of 8.1 K

Achieved quantum Hall plateaus with well-defined conductance quantization

Controlled channel properties using side gates

Abstract

Hybrid superconductor/semiconductor devices constitute a powerful platform where intriguing topological properties can be investigated. Here we present fabrication methods and analysis of Josephson junctions formed by a high-mobility InAs quantum-well bridging two Nb superconducting contacts. We demonstrate supercurrent flow with transport measurements, critical temperature of 8.1 K, and critical fields of the order of 3 T. Modulation of supercurrent amplitude can be achieved by acting on two side gates lithographed close to the two-dimensional electron gas. Low-temperature measurements reveal also well-developed quantum Hall plateaus, showing clean quantization of Hall conductance. Here the side gates can be used to manipulate channel width and electron carrier density in the device. These findings demonstrate the potential of these hybrid devices to investigate the coexistence of superconductivity and Quantum Hall effect and constitute the first step in the development of new device architectures hosting topological states of matter.