Signatures of single quantum dots in graphene nanoribbons within the quantum Hall regime

TL;DR

This paper reports the observation of conductance oscillations in suspended graphene nanoribbons within the quantum Hall regime, attributed to single quantum dots formed by disorder potential valleys and hills, with implications for gate-defined quantum dot creation.

Contribution

It demonstrates the formation of single quantum dots in graphene nanoribbons via electrostatic confinement enabled by Landau level gaps, and observes double-dot systems in a multi-gate setup.

Findings

Periodic conductance oscillations near quantum Hall plateaus.

Detection of single quantum dots in narrow graphene nanoribbons.

Observation of double-dot signatures in a two-gate device.

Abstract

We report on the observation of periodic conductance oscillations near quantum Hall plateaus in suspended graphene nanoribbons. They are attributed to single quantum dots that form in the narrowest part of the ribbon, in the valleys and hills of a disorder potential. In a wide flake with two gates, a double-dot system's signature has been observed. Electrostatic confinement is enabled in single-layer graphene due to the gaps that form between Landau levels, suggesting a way to create gate-defined quantum dots that can be accessed with quantum Hall edge states.