Excitonic Mott insulator in a Bose-Fermi-Hubbard system of moir'e $ m{WS}_2$/$ m{WSe}_2$ heterobilayer

ORAL

Abstract

Understanding the Hubbard model is crucial for investigating various quantum many-body states and its fermionic and bosonic versions have been largely realized separately. Recently, transition metal dichalcogenides heterobilayers have emerged as a promising platform for simulating the rich physics of the Hubbard model. In this work, we explore the interplay between fermionic and bosonic populations, using a $ m{WS}_2$/$ m{WSe}_2$ heterobilayer device that hosts this hybrid particle density. We independently tune the fermionic and bosonic populations by electronic doping and optical injection of electron-hole pairs, respectively. This enables us to form strongly interacting excitons that are manifested in a large energy gap in the photoluminescence spectrum. The incompressibility of excitons is further corroborated by ds{observing a suppression of} exciton diffusion ds{with increasing pump intensity}, as opposed to the expected behavior of a weakly interacting gas of bosons, suggesting the formation of a bosonic Mott insulator. We explain our observations using a two-band model including phase space filling. Our system provides a controllable approach to the exploration of quantum many-body effects in the generalized Bose-Fermi-Hubbard model.

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Publication: arXiv:2304.09731

Presenters

  • Beini Gao

    • University of Maryland, College Park

Authors

  • Beini Gao

    • University of Maryland, College Park

  • Daniel G Suárez Forero

    • University of Maryland, College Park

  • Supratik Sarkar

    • University of Waterloo

  • Tsung-Sheng Huang

    • University of Maryland, College Park

  • Deric Session

    • University of Maryland

  • Mahmoud Jalali Mehrabad

    • University of Maryland, College Park

  • Ruihao Ni

    • University of Maryland, College Park

  • Ming Xie

    • University of Maryland, College Park

  • Jonathan Vannucci

    • University of Maryland, College Park

  • Sunil Mittal

    • University of Maryland, College Park

  • 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

  • Atac Imamoglu

    • ETH Zurich

  • You Zhou

    • University of Maryland College Park

  • Mohammad Hafezi

    • University of Maryland, College Park