Equilibrium exciton insulator in semiconductor atomic double layers

ORAL

Abstract

Exciton insulator, a conductor for excitons but an insulator for charges, is expected to emerge in a material when its energy gap for charge excitations becomes smaller than the exciton binding energy, beyond which an exciton gas is spontaneously formed. Atomic double layers of transition metal dichalcogenide (TMD) semiconductor, which support large interlayer exciton binding energy, provide an ideal platform to realize exciton insulators with high ionization temperatures. We provide direct thermodynamic evidence for an equilibrium exciton insulator in TMD double layers. Using a new exciton-contact device design, we have created a charge-free equilibrium exciton fluid by continuously reducing the charge gap of the system below the exciton binding energy. Compressibility measurements show that the fluid is exciton-compressible but charge-imcompressible, directly demonstrating its exciton insulating character. We have further obtained a phase diagram for the strongly interacting exciton fluid.

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Presenters

  • Liguo Ma

    • Cornell University

Authors

  • Liguo Ma

    • Cornell University

  • Phuong Nguyen

    • Cornell University

  • Zefang Wang

    • Cornell University

  • Kenji Watanabe

    • National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institure for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • NIMS
    • National Institute of Materials Science
    • National Institute for Materials Science (NIMS)
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science,1-1 Namiki
    • National Institute of Material Science
    • National Institute for Materials Science, Tsukuba, Japan
    • Research Center for Functional Materials, NIMS
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institude for Materials Science
    • National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials
    • NIMS - Japan
    • National Institute for Materials Science ,Japan
    • National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
    • National Institute for Material Science
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Research Center for Functional Materials, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
    • National Institue for Material Science
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • Materials, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
    • Research Center for Functional Materials, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials nanoarchtectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • NIMS Suguba
    • NIMS, Tsukuba, Japan
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
    • National institute of material science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • Advanced Materials Laboratory, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
    • National Institute for Materials Science, Research Center for Functional Materials
    • National Institute of Material Science, Japan
    • Tsukuba, National Institute for Materials Science

  • Takashi Taniguchi

    • National Institute for Materials Science, Japan
    • National Institute for Materials Science
    • Department of Chemical Engineering, Kyoto University
    • National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • Materials, NIMS
    • International Center for Materials Anorthite, National Institute for Materials Science, Ibaraki, Japan
    • Kyoto University

  • Jie Shan

    • Cornell University

  • Kin Fai Mak

    • Cornell University