Experimental evidence for a collective insulating state in two-dimensional superconductors

TL;DR

This study provides experimental evidence of a collective insulating state in disordered two-dimensional superconductors induced by strong magnetic fields, characterized by a sharp conductance threshold and a transition from superconductivity to insulation.

Contribution

The paper demonstrates the existence of a new collective insulating state in 2D superconductors under high magnetic fields through detailed current-voltage measurements.

Findings

Differential conductance vanishes abruptly below a specific temperature.

A well-defined conduction threshold appears in the insulating phase.

Superconductivity degrades with increasing magnetic field until an insulating state emerges.

Abstract

We present the results of an experimental study of the current-voltage characteristics in strong magnetic field ($B$) of disordered, superconducting, thin-films of amorphous Indium-Oxide. As the $B$ strength is increased superconductivity degrades, until a critical field ($B_c$) where the system is forced into an insulating state. We show that the differential conductance measured in the insulating phase vanishes abruptly below a well-defined temperature, resulting in a clear threshold for conduction. Our results indicate that a new collective state emerges in two-dimensional superconductors at high $B$.