Interplay between the coherent and incoherent transport in quantum Hall bilayers

TL;DR

This paper investigates the relationship between coherent and incoherent charge transport in quantum Hall bilayers, revealing how Josephson tunneling and breakdown phenomena vary with interlayer distance and coexist with dissipative processes.

Contribution

It provides a systematic experimental analysis of coherent and incoherent transport mechanisms in quantum Hall bilayers at total filling factor 1.

Findings

Josephson currents vary significantly with interlayer distance

Breakdown thresholds are similar across different sample configurations

Coherent counterflow coexists with dissipative charge transport

Abstract

We systematically study the coherent transport (Josephson tunneling and counterflow current) and its breakdown which leads to incoherent charge flow in in the excitonic BCS condensate formed in GaAs bilayers at $\nu_{tot}=1/2+1/2$. The Josephson currents in samples with three different interlayer distances vary by four orders of magnitude. In contrast, the breakdown thresholds for the $\nu_{tot}=1$ quantum Hall state are comparable. Furthermore, Coulomb drag in a Corbino ring reveals that the coherent counterflow current coexists with the dissipative charge transport.