Dynamical Stabilization of Supercurrents in a Graphene-Based Josephson Network

ORAL

Abstract

Josephson networks are a promising platform for harboring synthetic topological phases of matter and Floquet states. These networks have hosted Cooper multiplets–coherent transport of four or more electrons through splitting of Cooper pairs and subsequent Andreev reflections. In this talk, we demonstrate multi-junction dynamical supercurrents emerging from an engineered Josephson network. The device features three superconducting electrodes connected through graphene to a superconducting island. The dynamical supercurrents include features similar to Cooper quartets, which are robust to elevated temperatures and exhibit the expected Shapiro step quantization under microwave drive. Additionally, we observe an unexpected supercurrent mediated between adjacent contacts through the superconducting island. These experimental results are substantiated by demonstrations of dynamical stabilization in the RCSJ model of the device.

*Transport measurements by E.G.A., J.C., T.F.Q.L. and C.C., and data analysis by E.G.A., F.A. and G.F. were supported by Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, U.S. Department of Energy, under Award No. DE-SC0002765. Lithographic fabrication and characterization of the samples by E.G.A., L.Z. and F.A. were supported by the NSF Award DMR-2004870. F.A. was supported by a URC grant at Appalachian State University. K.W. and T.T. acknowledge support from JSPS KAKENHI Grant Number JP15K21722 and the Elemental Strategy Initiative conducted by the MEXT, Japan. T.T. acknowledges support from JSPS Grant-in-Aid for Scientific Research A (No. 26248061) and JSPS Innovative Areas "Nano Informatics" (No. 25106006). This work was performed in part at the Duke University Shared Materials Instrumentation Facility (SMIF), a member of the North Carolina Research Triangle Nanotechnology Network (RTNN), which is supported by the National Science Foundation (Grant ECCS-1542015) as part of the National Nanotechnology Coordinated Infrastructure (NNCI).

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Presenters

  • John Chiles

    • Duke University

Authors

  • John Chiles

    • Duke University

  • Ethan G Arnault

    • Massachusetts Institute of Technology

  • Trevyn Larson

    • National Institute of Standards and Technology, Boulder

  • Chun-Chia Chen

    • Duke University

  • Lingfei Zhao

    • Department of Physics and Duke Quantum Center, Duke University, Durham, NC
    • Duke University

  • Kenji Watanabe

    • National Institute for Materials Science
    • NIMS
    • Research Center for Electronic and Optical Materials, National Institute for Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science

  • Takashi Taniguchi

    • Kyoto Univ
    • National Institute for Materials Science
    • Research Center for Materials Nanoarchitectonics
    • Research Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Sciences
    • NIMS
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, NIMS, Japan
    • International Center for Materials Nanoarchitectonics, Tsukuba
    • National Institue for Materials Science
    • Kyoto University
    • National Institute of Materials Science
    • International Center for Materials Nanoarchitectonics and National Institute for Materials Science

  • Francois Amet

    • Appalachian State University

  • Gleb Finkelstein

    • Duke University