Aharonov Bohm Effect in Graphene Fabry P\'erot Quantum Hall Interferometers

TL;DR

This paper reports the development of a graphene-based Fabry-Pérot quantum Hall interferometer that demonstrates clear Aharonov-Bohm interference in the integer quantum Hall regime, enabling advanced studies of quantum coherence and exchange statistics.

Contribution

We introduce a novel fabrication technique for graphene quantum Hall interferometers and successfully observe pure Aharonov-Bohm interference in a finite-sized device.

Findings

High visibility interference observed in integer edge modes

Long phase coherence lengths measured in the device

Platform enables future fractional quantum Hall experiments

Abstract

Quantum interferometers are powerful tools for probing the wave-nature and exchange statistics of indistinguishable particles. Of particular interest are interferometers formed by the chiral, one-dimensional (1D) edge channels of the quantum Hall effect (QHE) that guide electrons without dissipation. Using quantum point contacts (QPCs) as beamsplitters, these 1D channels can be split and recombined, enabling interference of charged particles. Such quantum Hall interferometers (QHIs) can be used for studying exchange statistics of anyonic quasiparticles. In this study we develop a robust QHI fabrication technique in van der Waals (vdW) materials and realize a graphene-based Fabry-P\'erot (FP) QHI. By careful heterostructure design, we are able to measure pure Aharonov-Bohm (AB) interference effect in the integer QHE, a major technical challenge in finite size FP interferometers. We find that integer edge modes exhibit high visibility interference due to relatively large velocities and long phase coherence lengths. Our QHI with tunable QPCs presents a versatile platform for interferometer studies in vdW materials and enables future experiments in the fractional QHE.