We demonstrate dispersive readout of individual charge states in a gate-defined few-electron quantum dot in bilayer graphene. We employ a radio frequency reflectometry circuit, where an LC resonator with a resonance frequency close to 280 MHz is directly coupled to an ohmic contact of the quantum dot device. The detection scheme based on changes in the quantum capacitance operates over a wide gate-voltage range and allows to probe excited states down to the single-electron regime. Crucially, the presented sensing technique avoids the use of an additional, capacitively coupled quantum device such as a quantum point contact or single electron transistor, making dispersive sensing particularly interesting for gate-defined graphene quantum dots.
@article{arxiv.2012.06221,
title = {Dispersive sensing of charge states in a bilayer graphene quantum dot},
author = {Luca Banszerus and Samuel Möller and Eike Icking and Corinne Steiner and Daniel Neumaier and Martin Otto and Kenji Watanabe and Takashi Taniguchi and Christian Volk and Christoph Stampfer},
journal= {arXiv preprint arXiv:2012.06221},
year = {2021}
}