Coulomb blockade in an atomically thin quantum dot coupled to a tunable Fermi reservoir

Mauro Brotons-Gisbert, Artur Branny, Santosh Kumar, Raphaël Picard, Raphaël Proux, Mason Gray, Kenneth S. Burch, Kenji Watanabe, Takashi Taniguchi, Brian D. Gerardot

Research output: Contribution to journalArticle

14 Citations (Scopus)
49 Downloads (Pure)

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 languageEnglish
Pages (from-to)442-446
Number of pages5
JournalNature Nanotechnology
Volume14
Issue number5
DOIs
Publication statusPublished - 11 Mar 2019

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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    Brotons-Gisbert, M., Branny, A., Kumar, S., Picard, R., Proux, R., Gray, M., Burch, K. S., Watanabe, K., Taniguchi, T., & Gerardot, B. D. (2019). Coulomb blockade in an atomically thin quantum dot coupled to a tunable Fermi reservoir. Nature Nanotechnology, 14(5), 442-446. https://doi.org/10.1038/s41565-019-0402-5