Magnetic field resistant quantum interferences in bismuth nanowires based Josephson junctions

TL;DR

This study demonstrates that bismuth nanowire-based Josephson junctions exhibit robust, magnetic field resistant supercurrents with complex interference patterns, driven by surface states and strong spin-orbit effects.

Contribution

It reveals magnetic field resistant quantum interference effects in bismuth nanowire Josephson junctions, highlighting the role of surface states and spin-orbit coupling.

Findings

Supercurrent persists above 11 T magnetic field.

Observation of SQUID-like oscillations in critical current.

Critical current modulations linked to surface states and spin effects.

Abstract

We investigate proximity induced superconductivity in micrometer-long bismuth nanowires con- nected to superconducting electrodes with a high critical field. At low temperature we measure a supercurrent that persists in magnetic fields as high as the critical field of the electrodes (above 11 T). The critical current is also strongly modulated by the magnetic field. In certain samples we find regular, rapid SQUID-like periodic oscillations occurring up to high fields. Other samples ex- hibit less periodic but full modulations of the critical current on Tesla field scales, with field-caused extinctions of the supercurrent. These findings indicate the existence of low dimensionally, phase coherent, interfering conducting regions through the samples, with a subtle interplay between orbital and spin contributions. We relate these surprising results to the electronic properties of the surface states of bismuth, strong Rashba spin-orbit coupling, large effective g factors, and their effect on the induced superconducting correlations.