Composite fermions and the field-tuned superconductor-insulator transition

TL;DR

This paper proposes that the metallic phases observed in 2D films near the superconductor-insulator transition are analogous to composite Fermi liquids, involving mobile vortices attached to flux quanta, and discusses their stability and experimental implications.

Contribution

It introduces a novel composite vortex liquid framework for understanding metallic phases in 2D superconductor-insulator transitions, extending the 'dirty boson' model with emergent gauge fields.

Findings

The composite vortex liquid is a stable non-Fermi liquid metal.

It predicts specific experimental signatures of the emergent phase.

The model explains the stability of metallic phases against disorder.

Abstract

In several two-dimensional films that exhibit a magnetic field-tuned superconductor to insulator transition (SIT), stable metallic phases have been observed. Building on the `dirty boson' description of the SIT, we suggest that the metallic region is analogous to the composite Fermi liquid observed about half-filled Landau levels of the two-dimensional electron gas. The composite fermions here are mobile vortices attached to one flux quantum of an emergent gauge field. The composite vortex liquid is a 2D non-Fermi liquid metal, which we argue is stable to weak quenched disorder. We describe several experimental consequences of the emergent composite vortex liquid.