Oral: Evidence for excitonic Mott insulator in WS<sub>2</sub>/WSe<sub>2</sub> moiré superlattice

ORAL

Abstract

Angle-aligned transition metal dichalcogenide(TMDC) heterojunction exhibits strongly enhanced electron-electron interaction because of the moiré superlattices, which provides an interesting platform for fermionic correlated states studies. This enhancement can also be inherited at the type II heterojunction (WS2/WSe2 junction) when the electron and hole are separated in two different layers, which leads to long-lived valley-polarized correlated bosonic quasiparticles. With helicity-resolved PL measurement as a function of excitation power, we are able to study the spatial extent of interlayer excitons, as well as the band hierarchy of correlated states that arise from the strong interaction between interlayer excitons and electrons. The measurements also show evidence that at the filling of one exciton per moiré cell, an excitonic Mott insulator state emerges, with the valley polarization enhanced by nearly one order of magnitude. Our study demonstrates the potential of WS2/WSe2 interlayer for the study of correlated states of fermion, bosons, and a mixture of both.

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Presenters

  • Yuze Meng

    • Rensselaer Polytechnic Institute

Authors

  • Yuze Meng

    • Rensselaer Polytechnic Institute

  • Zhen Lian

    • Rensselaer Polytechnic Institute

  • Lei Ma

    • Rensselaer Polytechnic Institute

  • Indrajit Maity

    • Imperial College London

  • Li Yan

    • Rensselaer polytechnic institute
    • Rensselaer Polytechnic Institute

  • Qiran Wu

    • University of California, Riverside

  • Xiong Huang

    • University of California, Riverside

  • Dongxue Chen

    • Rensselaer Polytechnic Institute

  • Xiaotong Chen

    • Rice University
    • Rensselaer Polytechnic Institute

  • Xinyue Chen

    • Rensselaer polytechnic institute
    • Rensselaer Polytechnic Institute

  • Mark Blei

    • Arizona State University

  • 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

  • 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

  • Sefaattin Tongay

    • FIAP
    • Arizona State University

  • Johannes C Lischner

    • Imperial College London

  • Yongtao Cui

    • University of California, Riverside

  • Sufei Shi

    • Rensselaer Polytechnic Institute