Coupling of Josephson Currents in Quantum Hall Bilayers

TL;DR

This paper investigates Josephson currents in Corbino devices made of bilayer quantum Hall systems, revealing controllable supercurrents mediated by interlayer excitonic states with minimal conductance between edges.

Contribution

It demonstrates the coupling of Josephson currents across edges in a quantum Hall bilayer, mediated by neutral excitonic ground states, a novel insight into interlayer coherence.

Findings

Identical Josephson currents observed at both edges.

Maximum Josephson current can be controlled via the other edge.

Negligible conductance between edges despite current coupling.

Abstract

We study ring shaped (Corbino) devices made of bilayer two-dimensional electron gases in the total filling factor one quantized Hall phase which is considered to be a coherent BCS-like state of interlayer excitons. Identical Josephson currents are observed at the two edges while only a negligible conductance between them is found. The maximum Josephson current observed at either edge can be controlled by passing a second interlayer Josephson current at the other edge. Due to the large electric resistance between the two edges, the interaction between them can only be mediated by the neutral interlayer excitonic groundstate.