Bose-Einstein Condensation of Excitons in Bilayer Electron Systems

TL;DR

This paper reviews recent experimental evidence for Bose-Einstein condensation of excitons in semiconductor bilayer systems within the quantum Hall regime, highlighting the conditions and implications of this phenomenon.

Contribution

It provides a comprehensive review of recent studies demonstrating exciton condensation in bilayer electron systems, emphasizing the role of disorder and quantum Hall effects.

Findings

Clear experimental evidence of exciton condensation in bilayer systems

Disorder-induced vortices affect supercurrent flow

Quantum Hall regime facilitates exciton condensation in electron-electron bilayers

Abstract

An ordered state of electrons in solids in which excitons condense was proposed many years ago as a theoretical possibility but has, until recently, never been observed. We review recent studies of semiconductor bilayer systems that provide clear evidence for this phenomenon and explain why exciton condensation in the quantum Hall regime, where these experiments were performed, is as likely to occur in electron-electron bilayers as in electron-hole bilayers. In current quantum Hall exciton condensates, disorder induces mobile vortices that flow in response to a supercurrent and limit the extremely large bilayer counterflow conductivity.