Radio-frequency reflectometry in bilayer graphene devices utilizing micro graphite back-gates

TL;DR

This paper demonstrates RF-reflectometry in bilayer graphene devices using micro graphite back-gates, enabling high-speed quantum dot measurements and advancing quantum device research.

Contribution

It introduces a novel RF-reflectometry setup for bilayer graphene with micro graphite back-gates, improving measurement speed and device characterization.

Findings

RF-reflectometry setup was successfully implemented in bilayer graphene.

Resonance properties of the tank circuit were measured and matched with DC results.

Coulomb diamonds of quantum dots were observed and confirmed via RF-reflectometry.

Abstract

Bilayer graphene is an attractive material that realizes high-quality two-dimensional electron gas with a controllable bandgap. By utilizing the bandgap, electrical gate tuning of the carrier is possible and formation of nanostructures such as quantum dots have been reported. To probe the dynamics of the electronics states and realize applications for quantum bit devices, RF-reflectometry which enables high-speed electric measurements is important. Here we demonstrate RF-reflectometry in bilayer graphene devices. We utilize a micro graphite back-gate and an undoped Si substrate to reduce the parasitic capacitance which degrades the RF-reflectometry. We measure the resonance properties of a tank circuit which contains the bilayer graphene device. We form RF-reflectmetory setup and compared the result with the DC measurement, and confirmed their consistency. We also measure Coulomb diamonds of quantum dots possibly formed by bubbles and confirm that RF-reflectometry of quantum dots can be performed. This technique enables high-speed measurements of bilayer graphene quantum dots and contributes to the research of bilayer graphene-based quantum devices by fast readout of the states.