A tunable Fabry-P\'erot quantum Hall interferometer in graphene

TL;DR

This paper demonstrates a tunable Fabry-Pérot quantum Hall interferometer in graphene that exhibits high-visibility interference free of charging effects, enabling advanced studies of topological excitations for quantum computing.

Contribution

It introduces a graphene-based, gate-tunable quantum Hall interferometer with high coherence and tunability, overcoming previous challenges in semiconductor systems.

Findings

High-visibility Aharonov-Bohm interference observed

Interference tunable via electrostatic gating and magnetic field

Coherence length of 10 micrometers at 0.02 K

Abstract

Electron interferometry with quantum Hall edge channels holds promise for probing and harnessing exotic exchange statistics of non-Abelian anyons. In semiconductor heterostructures, however, quantum Hall interferometry has proven challenging and often obscured by charging effects. Here we show that high-mobility monolayer graphene equipped with a series of gate-tunable quantum point contacts that act as electron beam-splitters provides a model system to perform Fabry-P\'{e}rot quantum Hall interferometry. We observe high-visibility Aharonov-Bohm interference free of charging effects and widely tunable through electrostatic gating or magnetic field, in remarkable agreement with theory. A coherence length of $\mathbf{10 \,\mu m}$ at a temperature of $0.02$ K allows us to further achieve coherently-coupled double Fabry-P\'{e}rot interferometry. Our results open a new avenue for quantum Hall interferometry and the exploitation of topological excitations for quantum computation.