Evidence of local superconductivity in granular Bi nanowires fabricated by electrodeposition

TL;DR

This paper reports evidence of local superconductivity in granular bismuth nanowires, indicated by superresistivity behavior that depends on magnetic field and current, suggesting nucleation of superconductivity without global coherence.

Contribution

It provides experimental evidence of local superconductivity in granular Bi nanowires, a phenomenon not previously demonstrated in this material system.

Findings

Superresistivity observed below a characteristic temperature Tsr

Superresistivity depends on magnetic field and excitation current

Behavior resembles that of local superconductivity without long-range coherence

Abstract

An unusual enhancement of resistance (i.e., superresistivity) below a certain characteristic temperature Tsr was observed in granular Bi nanowires. This superresistive state was found to be dependent on the applied magnetic field (H) as well as the excitation current (I). The suppression of Tsr by magnetic field resembles that of a superconductor. The observed superresistivity appears to be related to the nucleation of local superconductivity inside the granular nanowire without long-range phase coherence. The phenomenon is reminiscent of the Bose-insulator observed previously in ultra thin two-dimensional (2D) superconducting films and 3D percolative superconducting films.