Enhanced Superconductivity and Suppression of Charge-density Wave Order in 2H-TaS<sub>2</sub> in the Two-dimensional Limit

ORAL

Abstract

As superconductors are thinned down to the 2D limit, their critical temperature Tc typically decreases. Here we report the opposite behavior, an enhancement of Tc with decreasing thickness, in the 2D crystalline superconductor 2H-TaS2. Remarkably, in the monolayer limit, Tc increases by over a factor of four compared to bulk crystals. Accompanying this trend in superconductivity, we observe progressive weakening and suppression of the charge-density wave (CDW) transition with decreasing thickness. To explain these trends, we perform electronic structure calculations showing that a reduction of the CDW amplitude results in a substantial increase of the density of states at the Fermi energy, which contributes to the enhancement of Tc.
Our results provide insights into superconductivity, CDW order, and their mutual interaction in reduced dimensions.

*We acknowledge US DOE, BES Office, DMSE Award DE-SC0001819 (YY and PJH) and the Gordon and Betty Moore Foundation’s EPiQS Initiative Grant GBMF4541. Theory was supported by the NSF-STC CIQM No. DMR-1231319 (VF, SF) and ARO MURI Award W911NF-14-0247 (EK).

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Presenters

  • Yafang Yang

    • Department of Physics, Massachusetts Institute of Technology
    • Massachusetts Inst of Tech-MIT

Authors

  • Yafang Yang

    • Department of Physics, Massachusetts Institute of Technology
    • Massachusetts Inst of Tech-MIT

  • Shiang Fang

    • Department of Physics, Harvard University
    • Harvard University

  • Valla Fatemi

    • Massachusetts Inst of Tech-MIT
    • Massachusetts Institute of Technology

  • Jonathan Ruhman

    • Massachusetts Inst of Tech-MIT
    • Condensed matter theory , Massachusetts Inst of Tech-MIT
    • Physics, Massachusetts Institute of Technology

  • Efren Navarro-Moratalla

    • Massachusetts Institute of Technology
    • Instituto de Ciencia Molecular, Universidad de Valencia

  • Kenji Watanabe

    • National Institute for Materials Science
    • NIMS
    • National Institute for Material Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science (NIMS
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Advanced Materials Laboratory
    • National Institue for Materials Science
    • National Institute of Material Science
    • National Institute for Matericals Science
    • Advanced Materials Laboratory
    • National Institute for Materials Science, 1-1 Namiki
    • Advanced materials laboratory, National institute for Materials Science
    • NIMS-Japan

  • Takashi Taniguchi

    • National Institute for Materials Science
    • NIMS
    • National Institute for Material Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science (NIMS
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Advanced Materials Laboratory
    • National Institue for Materials Science
    • National Institute of Material Science
    • National Institute for Matericals Science
    • Advanced Materials Laboratory
    • National Institute for Materials Science, 1-1 Namiki
    • NIMS-Japan

  • Efthimios Kaxiras

    • Department of Physics, Harvard University
    • Harvard Univ
    • Harvard University
    • Physics, Harvard University
    • School of Engineering and Applied Science, Harvard University

  • Pablo Jarillo-Herrero

    • Massachusetts Inst of Tech-MIT
    • Department of Physics, Massachusetts Institute of Technology
    • Physics, MIT
    • MIT
    • Massachusetts Institute of Technology