Abstract
Gate-tunable quantum-mechanical tunnelling of particles between a quantum confined state and a nearby Fermi reservoir of delocalized states has underpinned many advances in spintronics and solid-state quantum optics. The prototypical example is a semiconductor quantum dot separated from a gated contact by a tunnel barrier. This enables Coulomb blockade, the phenomenon whereby electrons or holes can be loaded one-by-one into a quantum dot1,2. Depending on the tunnel-coupling strength3,4, this capability facilitates single spin quantum bits1,2,5 or coherent many-body interactions between the confined spin and the Fermi reservoir6,7. Van der Waals (vdW) heterostructures, in which a wide range of unique atomic layers can easily be combined, offer novel prospects to engineer coherent quantum confined spins8,9, tunnel barriers down to the atomic limit10 or a Fermi reservoir beyond the conventional flat density of states11. However, gate-control of vdW nanostructures12-16 at the single particle level is needed to unlock their potential. Here we report Coulomb blockade in a vdW heterostructure consisting of a transition metal dichalcogenide quantum dot coupled to a graphene contact through an atomically thin hexagonal boron nitride (hBN) tunnel barrier. Thanks to a tunable Fermi reservoir, we can deterministically load either a single electron or a single hole into the quantum dot. We observe hybrid excitons, composed of localized quantum dot states and delocalized continuum states, arising from ultra-strong spin-conserving tunnel coupling through the atomically thin tunnel barrier. Probing the charged excitons in applied magnetic fields, we observe large gyromagnetic ratios (∼8). Our results establish a foundation for engineering next-generation devices to investigate either novel regimes of Kondo physics or isolated quantum bits in a vdW heterostructure platform.
Original language | English |
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Pages (from-to) | 442-446 |
Number of pages | 5 |
Journal | Nature Nanotechnology |
Volume | 14 |
Issue number | 5 |
DOIs | |
Publication status | Published - 11 Mar 2019 |
ASJC Scopus subject areas
- Bioengineering
- Atomic and Molecular Physics, and Optics
- Biomedical Engineering
- General Materials Science
- Condensed Matter Physics
- Electrical and Electronic Engineering
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Addtional Data for Coulomb blockade in an atomically thin quantum dot strongly coupled to a tunable Fermi reservoir
Gerardot, B. D. (Creator) & Brotons i Gisbert, M. (Creator), Heriot-Watt University, 9 Nov 2018
DOI: 10.17861/fe40f6e2-f6a4-4289-8207-707aac8a03aa
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Profiles
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Brian D. Gerardot
- School of Engineering & Physical Sciences - Professor
- School of Engineering & Physical Sciences, Institute of Photonics and Quantum Sciences - Professor
Person: Academic (Research & Teaching)