Superinsulator as a phase of bi-particle localized states

TL;DR

This paper proposes that superinsulators are a phase of bi-particle localized states caused by electron pairing, which can be broken by a static electric field leading to a sharp transition observed experimentally.

Contribution

It introduces a new physical picture of superinsulators as bi-particle localized states and links their breakdown to a static electric field, supported by numerical simulations.

Findings

Localized pairs are broken by a static electric field above a threshold.

Breaking of pairs explains the superinsulator's critical voltage and current jump.

Moderate attraction creates bi-particle localized states at intermediate disorder.

Abstract

We propose a physical picture of superinsulator observed recently in experiments with superconducting films in a magnetic field. On the basis of previous numerical studies we argue that a moderate attraction creates bi-particle localized states at intermediate disorder strength when noninteracting electron states are delocalized and metallic. Our present numerical study show that such localized pairs are broken by a static electric field which strength is above a certain threshold. We argue that such a breaking of localized pairs by a static field is at the origin of superinsulator breaking with a current jump observed experimentally above a certain critical voltage.