Very Strong Superconducting Proximity Effects in PbS Semiconductor Nanowires

TL;DR

This paper demonstrates the fabrication of highly efficient superconducting junctions using PbS semiconductor nanowires with record supercurrent values, confirming Josephson coupling and potential for quantum device applications.

Contribution

It presents the first demonstration of strongly coupled PbS nanowire-based superconducting junctions with record supercurrent and clear Josephson effects, advancing quantum device technology.

Findings

Maximum supercurrent of ~15 μA at 0.3 K

Observation of microwave-induced voltage steps confirming Josephson coupling

Critical current suppression consistent with narrow junction model

Abstract

We report the fabrication of strongly coupled nanohybrid superconducting junctions using PbS semiconductor nanowires and Pb0.5In0.5 superconducting electrodes. The maximum supercurrent in the junction reaches up to ~15 \mu A at 0.3 K, which is the highest value ever observed in semiconductor-nanowire-based superconducting junctions. The observation of microwave-induced constant voltage steps confirms the existence of genuine Josephson coupling through the nanowire. Monotonic suppression of the critical current under an external magnetic field is also in good agreement with the narrow junction model. The temperature-dependent stochastic distribution of the switching current exhibits a crossover from phase diffusion to a thermal activation process as the temperature decreases. These strongly coupled nanohybrid superconducting junctions would be advantageous to the development of gate-tunable superconducting quantum information devices.