Role of the compensating current in the weak Josphson coupling regime: An extended study on excitonic Josephson junctions

TL;DR

This paper investigates the role of the compensating current in excitonic Josephson junctions within the weak coupling regime, revealing a nonequilibrium phase transition and providing new experimental predictions.

Contribution

It extends previous studies by analyzing the weak Josephson coupling regime, uncovering a phase transition driven by the compensating current, and identifying critical behavior.

Findings

Compensating current induces a nonequilibrium phase transition.

Abrupt jump in critical tunneling current observed.

Critical exponent and experimental predictions provided.

Abstract

Huang's experiment [Phys. Rev. Lett. $\bf 109$, 156802 (2012)] found, in the quantum Hall bilayer of the Corbino geometry, the interlayer tunneling currents at two edges are coupled to each other and one of two tunneling currents is referred to as the compensating current of the other. Our another work[arXiv:2006.15329] has explained this exotic coupling phenomenon as a result of excitonic Josephson effect induced by interlayer tunneling current. In this paper, we study the same setup -- excitonic Josephson junction -- but in the weak Josephson coupling regime, which occurs for large junction length. Interestingly, we find the compensating current drives the other edge to undergo a nonequilibrium phase transition from a superfluid to resistive state, which is signaled by an abrupt jump of the critical tunneling current. We also identify the critical exponent and furthermore offer more experimental prediction.