Residual quantum coherent electron transport in doped graphene leads

TL;DR

This study investigates the quantum transport properties of doped graphene leads in the quantum Hall regime, revealing preserved coherence and chirality despite charge equilibration, which informs better contact design in 2D materials.

Contribution

It provides new experimental insights into the transport behavior of doped graphene leads at low temperatures and high magnetic fields, enhancing understanding of their quantum coherence properties.

Findings

Electronic phase coherence is preserved in doped graphene leads.

Transport chirality remains intact despite charge equilibration.

Insights enable improved contact quality in 2D material devices.

Abstract

Recent low-temperature electron transport experiments in high-quality graphene rely on a technique of doped graphene leads, where the coupling between the graphene flake and its metallic contacts is increased by locally tuning graphene to high doping near the contacts. While this technique is widely used and has demonstrated its usefulness numerous times, little is known about the actual transport properties of the doped graphene leads. Here, we present an experiment probing those properties in the quantum Hall regime at low temperature and high magnetic field, showing that electronic phase coherence and transport chirality are preserved, despite the significant charge equilibration occurring at the edges of the leads. Our work yields a finer understanding of the properties of the doped graphene leads, allowing for improvements of the contact quality that can be applied to other two-dimensional materials.