Graphene-based quantum Hall interferometer with self-aligned side gates

TL;DR

This paper introduces a straightforward method to fabricate graphene quantum point contacts and interferometers using etched trenches and self-aligned side gates, enabling quantum Hall regime operation despite graphene's zero band gap.

Contribution

It presents a novel fabrication technique for graphene QPCs with self-aligned side gates, overcoming previous challenges related to graphene's zero band gap.

Findings

Successful operation of graphene QPCs in the quantum Hall regime

Demonstration of a graphene quantum Hall interferometer

Enhanced control over quantum Hall edge states

Abstract

The vanishing band gap of graphene has long presented challenges for making high-quality quantum point contacts (QPCs) -- the partially transparent p-n interfaces introduced by conventional split-gates tend to short the QPC. This complication has hindered the fabrication of graphene quantum Hall Fabry-P\'erot interferometers, until recent advances have allowed split-gate QPCs to operate utilizing the highly resistive $\nu=0$ state. Here, we present a simple recipe to fabricate QPCs by etching a narrow trench in the graphene sheet to separate the conducting channel from self-aligned graphene side gates. We demonstrate operation of the individual QPCs in the quantum Hall regime, and further utilize these QPCs to create and study a quantum Hall interferometer.