Quantum Hall Effect and Quantum Point Contact in Bilayer-Patched Epitaxial Graphene

TL;DR

This study investigates how bilayer inclusions in epitaxial graphene influence electron transport, revealing their role as conductive shorts or guides depending on their electronic state, with implications for quantum electronic devices.

Contribution

It provides new insights into the impact of bilayer inclusions on magnetotransport and electron flow in epitaxial graphene, combining experimental techniques.

Findings

Bilayer inclusions can be metallic or insulating based on carrier density.

Metallic bilayers act as equipotential shorts for edge currents.

Insulating bilayers guide electron flow in the monolayer.

Abstract

We study an epitaxial graphene monolayer with bilayer inclusions via magnetotransport measurements and scanning gate microscopy at low temperatures. We find that bilayer inclusions can be metallic or insulating depending on the initial and gated carrier density. The metallic bilayers act as equipotential shorts for edge currents, while closely spaced insulating bilayers guide the flow of electrons in the monolayer constriction, which was locally gated using a scanning gate probe.