Bosonic Mott insulator of interlayer excitons in transition metal dichalcogenide heterostructure

ORAL

Abstract

A panoply of unconventional electronic states is recently observed in moiré superlattices. On the other hand, similar opportunities to engineer bosonic phases remain largely unexplored. Here we report the observation of a bosonic Mott insulator in WSe2/WS2 moiré superlattices composed of excitons, i.e., tightly bound electron-hole pairs. Using a novel pump probe spectroscopy, we find an exciton incompressible state at exciton filling vex = 1 and charge neutrality, which we assign to a bosonic Mott insulator. When further varying charge density, the bosonic Mott insulator continuously transitions into an electron Mott insulator at charge filling ve = 1, suggesting a mixed Mott insulating state in between. Our observations are well captured by a mixed Hubbard model involving both fermionic and bosonic components, from which we extract the on-site Coulomb repulsion to be 15meV and 35meV for exciton-exciton and electron-exciton interactions, respectively. Our studies establish semiconducting moiré superlattices as intriguing platforms for engineering novel bosonic phases.

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Publication: arXiv:2207.10764

Presenters

  • Richen Xiong

    • University of California, Santa Barbara

Authors

  • Richen Xiong

    • University of California, Santa Barbara

  • Jacob Nie

    • University of California, Santa Barbara

  • Samual Brantly

    • University of California, Santa Barbara

  • Patrick Heys

    • Arizona State University

  • Renee Sailus

    • Arizona State University

  • Kenji Watanabe

    • National Institute for Materials Science
    • Research Center for Functional Materials, National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Takashi Taniguchi

    • National Institute for Materials Science
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute of Materials Science
    • Kyoto University
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute For Materials Science
    • NIMS
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Sefaattin Tongay

    • Arizona State University
    • FIAP

  • Chenhao Jin

    • University of California, Santa Barbara