A Mechanically Tunable Quantum Dot in a Graphene Break Junction

Sabina Caneva, Matthijs Hermans, Martin Lee, Amador García-Fuente, Kenji Watanabe, Takashi Taniguchi, Cees Dekker, Jaime Ferrer, Herre S.J. Van Der Zant, Pascal Gehring*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Graphene quantum dots (QDs) are intensively studied as platforms for the next generation of quantum electronic devices. Fine tuning of the transport properties in monolayer graphene QDs, in particular with respect to the independent modulation of the tunnel barrier transparencies, remains challenging and is typically addressed using electrostatic gating. We investigate charge transport in back-gated graphene mechanical break junctions and reveal Coulomb blockade physics characteristic of a single, high-quality QD when a nanogap is opened in a graphene constriction. By mechanically controlling the distance across the newly formed graphene nanogap, we achieve reversible tunability of the tunnel coupling to the drain electrode by 5 orders of magnitude, while keeping the source-QD tunnel coupling constant. The break junction device can therefore become a powerful platform to study the physical parameters that are crucial to the development of future graphene-based devices, including energy converters and quantum calorimeters.

Original languageEnglish
Pages (from-to)4924-4931
JournalNano Letters
Issue number7
Publication statusPublished - 2020


  • graphene
  • mechanical break junction
  • quantum dot (QD)
  • tunnel coupling

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