Electrostatic detection of Shubnikov-de-Haas oscillations in bilayer graphene by Coulomb resonances in gate-defined quantum dots

TL;DR

This paper demonstrates how a quantum dot in bilayer graphene can detect Shubnikov-de-Haas oscillations via Coulomb resonance shifts, providing a sensitive method to probe charge density variations under magnetic fields.

Contribution

It introduces a novel electrostatic detection technique for quantum oscillations in bilayer graphene using Coulomb resonances in gate-defined quantum dots.

Findings

Charge carrier density oscillates with magnetic field due to Landau levels.

Coulomb resonance shifts accurately reflect local charge density changes.

Experimental results agree well with electrostatic simulations.

Abstract

A gate-defined quantum dot in bilayer graphene is utilized as a sensitive electrometer for probing the charge density of its environment. Under the influence of a perpendicular magnetic field, the charge carrier density of the channel region next to the quantum dot oscillates due to the formation of Landau levels. This is experimentally observed as oscillations in the gate-voltage positions of the Coulomb resonances of the nearby quantum dot. From the frequency of the oscillations, we extract the charge carrier density in the channel and from the amplitude the shift of the quantum dot potential. We compare these experimental results with an electrostatic simulation of the device and find good agreement.