Observation of Critical Amplitude Fluctuations near the Two Dimensional Superconductor-Insulator Transition

TL;DR

This study investigates the critical amplitude fluctuations near the 2D superconductor-insulator transition, revealing increased transition width, inhomogeneity, and large amplitude fluctuations as disorder suppresses superconductivity.

Contribution

It provides experimental evidence of critical amplitude fluctuations and inhomogeneity near the 2D SIT, highlighting the role of disorder in driving the transition.

Findings

Transition width diverges at the SIT

Development of structure in DC I-V characteristics

Evidence of large amplitude fluctuations near the transition

Abstract

We report results of transport measurements in the quantum critical regime of the disorder tuned, 2D superconductor-insulator transition (SIT) in homogeneously disordered films. We show that, as the superconducting transition temperature decreases, the transition width grows, appearing to diverge at the SIT. In addition, structure develops in the DC current-voltage characteristics of films closest to the SIT indicating that the 2D superconductivity is driven into a regime of extreme inhomogeneity. The data suggest a picture of the phase transition in which large amplitude fluctuations occur as the amplitude is suppressed to near zero by disorder.