Gauge Topological Nature of the Superconductor-Insulator Transition

TL;DR

This paper presents a topological gauge theory framework for the superconductor-insulator transition, revealing that the intermediate Bose metal phase is a Mott topological insulator with confined Cooper pairs.

Contribution

It introduces a topological gauge description of the SIT, identifying superinsulation as Polyakov's confinement and characterizing the Bose metal as a Mott topological insulator.

Findings

Superinsulation arises from linear confinement of Cooper pairs.

The Bose metal phase is a Mott topological insulator.

Conditions for direct or intermediate SIT are derived.

Abstract

It has long been believed that, at absolute zero, electrons can form only one quantum coherent state, a superconductor. Yet, several two dimensional superconducting systems were found to harbor the superinsulating state with infinite resistance, a mirror image of superconductivity, and a metallic state often referred to as Bose metal, characterized by finite longitudinal and vanishing Hall resistances. The nature of these novel and mysterious quantum coherent states is the subject of intense study.Here, we propose a topological gauge description of the superconductor-insulator transition (SIT) that enables us to identify the underlying mechanism of superinsulation as Polyakov's linear confinement of Cooper pairs via instantons. We find a criterion defining conditions for either a direct SIT or for the SIT via the intermediate Bose metal and demonstrate that this Bose metal phase is a Mott topological insulator in which the Cooper pair-vortex liquid is frozen by Aharonov-Bohm interactions.