Exciton Condensation in Bilayer Quantum Hall Systems

TL;DR

This paper reviews the phenomenon of exciton condensation in bilayer quantum Hall systems, highlighting its unique properties, experimental observations, and implications for understanding quantum electronic phases.

Contribution

It provides a comprehensive overview of exciton condensation in bilayer quantum Hall systems, emphasizing recent experimental findings and theoretical insights.

Findings

Observation of exciton condensation phenomena

Electrical effects arising from exciton transport

Insights into quantum electronic matter phases

Abstract

The condensation of excitons, bound electron-hole pairs in a solid, into a coherent collective electronic state was predicted over 50 years ago. Perhaps surprisingly, the phenomenon was first observed in a system consisting of two closely-spaced parallel two-dimensional electron gases in a semiconductor double quantum well. At an appropriate high magnetic field and low temperature, the bilayer electron system condenses into a state resembling a superconductor, only with the Cooper pairs replaced by excitons comprised of electrons in one layer bound to holes in the other. In spite of being charge neutral, the transport of excitons within the condensate gives rise to several spectacular electrical effects. This article describes these phenomena and examines how they inform our understanding of this unique phase of quantum electronic matter.