Nanotransformation and current fluctuations in exciton condensate junctions

TL;DR

This paper investigates the nonlinear electron transport in bilayer exciton condensates with four metallic contacts, revealing unique features distinct from superconductors and proposing applications in nanoscale voltage transformation.

Contribution

It provides a comprehensive analysis of full counting statistics and predicts novel nonlinear transconductance and current correlations in exciton condensate junctions.

Findings

Distinct transport properties from superconductors.

Predicted nonlinear transconductance and current correlations.

Potential for nanoscale voltage transformation using excitonic Andreev reflections.

Abstract

We analyze the nonlinear transport properties of a bilayer exciton condensate that is contacted by four metallic leads by calculating the full counting statistics of electron transport for arbitrary system parameters. Despite its formal similarity to a superconductor the transport properties of the exciton condensate turn out to be completely different. We recover the generic features of exciton condensates such as counterpropagating currents driven by excitonic Andreev reflections and make predictions for nonlinear transconductance between the layers as well as for the current (cross)correlations and generalized Johnson-Nyquist relationships. Finally, we explore the possibility of connecting another mesoscopic system (in our case a quantum point contact) to the bottom layer of the exciton condensate and show how the excitonic Andreev reflections can be used for transforming voltage at the nanoscale.