Interactions in Electronic Mach-Zehnder Interferometers with Copropagating Edge Channels

TL;DR

This paper investigates how Coulomb interactions affect the behavior of Mach-Zehnder interferometers with copropagating edge channels in the quantum Hall regime, revealing phenomena like current saturation and negative differential conductance.

Contribution

It provides a detailed analysis of interaction effects on interferometer response, highlighting novel features such as current saturation and diverging visibility not previously characterized.

Findings

Interactions cause saturation of the interferometer current with bias voltage.

Negative differential conductance emerges due to Coulomb interactions.

Visibility of the current can be enhanced or diverge, indicating complex interference effects.

Abstract

We study Coulomb interactions in the finite bias response of Mach-Zehnder interferometers, which exploit copropagating edge states in the integer quantum Hall effect. Here, interactions are particularly important since the coherent coupling of edge channels is due to a resonant mechanism that is spoiled by inelastic processes. We find that interactions yield a saturation, as a function of bias voltage, of the period-averaged interferometer current, which gives rise to unusual features, such as negative differential conductance, enhancement of the visibility of the current, and nonbounded or even diverging visibility of the differential conductance.