Proximitized insulators from disordered superconductors

TL;DR

This study investigates how superconducting fluctuations in disordered bilayers induce insulating behavior through the proximity effect, revealing new insights into the superconductor-insulator transition in disordered systems.

Contribution

It provides experimental evidence of a novel proximity effect where superconducting fluctuations induce insulation, advancing understanding of the superconductor-insulator transition in disordered materials.

Findings

Superconducting fluctuations induce insulating behavior in proximitized disordered metals.

Suppression of the density of states due to the superconducting gap explains the insulating phase.

The results reveal a new manifestation of the proximity effect in disordered systems.

Abstract

We present an experimental study of bilayers of a disordered Ag metal layer close to the metal-insulator transition and an Indium Oxide film which is on the insulating side of the superconductor-insulator-transition. Our results show that superconducting fluctuations within the indium-oxide film, that proximitize the underlying metal layer, induce insulating rather than superconducting behavior. This is ascribed to suppression of density of states (due to the superconducting energy gap) for quasiparticles in the proximitized regions. Our results present a novel manifestation of the proximity effect phenomenon and provide important insight into the nature of the insulating phase of the disorder driven superconductor-insulator-transition.