Interaction-induced interference in the integer quantum Hall effect

TL;DR

This paper investigates how interactions between edge channels in the integer quantum Hall effect influence interference patterns, revealing that adjacent edge channels significantly affect coherence and periodicity, and highlighting the role of neutral modes in electron pairing.

Contribution

It demonstrates that the interference periodicity and coherence are governed by neighboring edge channels, emphasizing the influence of neutral chiral modes in the quantum Hall regime.

Findings

Interference periodicity is determined by adjacent edge channels.

Neutral chiral edge modes are crucial for electron pairing.

Observed pairing is a manifestation of complex edge physics.

Abstract

In recent interference experiments with an electronic Fabry-Perot interferometer (FPI), implemented in the integer quantum Hall effect regime, a flux periodicity of $h/2e$ was observed at bulk fillings $\nu_B>2.5$. The halved periodicity was accompanied by an interfering charge $e^*=2e$, determined by shot noise measurements. Here, we present measurements, demonstrating that, counterintuitively, the coherence and the interference periodicity of the interfering chiral edge channel are solely determined by the coherence and the enclosed flux of the adjacent edge channel. Our results elucidate the important role of the latter and suggest that a neutral chiral edge mode plays a crucial role in the pairing phenomenon. Our findings reveal that the observed pairing of electrons is not a curious isolated phenomenon, but one of many manifestations of unexpected edge physics in the quantum Hall effect regime.