Spectroscopy of NbSe2Using Energy-Tunable Defect-Embedded Quantum Dots

T. R. Devidas, Itai Keren, Hadar Steinberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Quantum dots have sharply defined energy levels, which can be used for high resolution energy spectroscopy when integrated in tunneling circuitry. Here we report dot-assisted spectroscopy measurements of the superconductor NbSe2, using a van der Waals device consisting of a vertical stack of graphene-MoS2-NbSe2. The MoS2 tunnel barriers host naturally occurring defects which function as quantum dots, allowing transport via resonant tunneling. The dot energies are tuned by an electric field exerted by a back-gate, which penetrates the graphene source electrode. Scanning the dot potential across the superconductor Fermi energy, we reproduce the NbSe2 density of states which exhibits a well-resolved two-gap spectrum. Surprisingly, we find that the dot-assisted current is dominated by the lower energy feature of the two NbSe2 gaps, possibly due to a selection rule which favors coupling between the dots and the orbitals which exhibit this gap.

Original languageAmerican English
Pages (from-to)6931-6937
Number of pages7
JournalNano Letters
Volume21
Issue number16
DOIs
StatePublished - 25 Aug 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society.

Keywords

  • 2 band superconductivity
  • NbSe
  • Quantum Dot
  • Resonant Tunneling

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