Observation of Wigner crystal of electrons in a monolayer semiconductor

ORAL

Abstract

If the Coulomb repulsion between the electrons becomes significantly stronger than their kinetic energy, the itinerant electrons in the two-dimensional systems are expected to form a Wigner crystal (WC). Here we provide a direct evidence that the electrons at densities < 3×1011 cm-2 in a MoSe2 monolayer spontaneously break continuous translation symmetry and form a WC even at B = 0 [*]. This is revealed by our low-temperature (T = 80 mK) optical experiments that utilize a newly developed technique of detecting a charge order. This method is based on the observation of the exciton umklapp or, equivalently, Bragg scattering off the WC that gives rise to emergence of a new, umklapp peak in the optical excitation spectrum. By tracing the evolution of this peak with the magnetic field and electron density we determined the WC phase properties at fields up to B = 16 T. We provide a qualitative explanation of these findings with a tentative phase-diagram obtained from our Hartree-Fock calculations. Altogether, our results evidence that gate-controlled TMD monolayers allow for exploration of strongly-correlated electronic states in previously inaccessible regime where inter-electron interactions are much stronger than the kinetic energy.

[*] T. Smolenski et al., arXiv:2010.03078 (2020)

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Presenters

  • Tomasz Smolenski

    • Institute for Quantum Electronics, ETH Zurich

Authors

  • Tomasz Smolenski

    • Institute for Quantum Electronics, ETH Zurich

  • Pavel Dolgirev

    • Department of Physics, Harvard University

  • Clemens Kuhlenkamp

    • Institute for Quantum Electronics, ETH Zurich

  • Alexander Popert

    • Institute for Quantum Electronics, ETH Zurich

  • Yuya Shimazaki

    • Institute for Quantum Electronics, ETH Zurich

  • Patrick Back

    • Institute for Quantum Electronics, ETH Zurich

  • Martin Kroner

    • Institute for Quantum Electronics, ETH Zurich

  • 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
    • 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)
    • International Center for Materials Nanoarchitectonics, 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
    • International Center for Materials Nanoarchitectonics, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institude for Materials Science
    • International Center for Materials Nanoarchitectonics, 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
    • 8International Center for Materials Nanoarchitectonics
    • NIMS Tsukuba
    • 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
    • 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
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • International Center for Material Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials Nanoarchitectonics
    • NIMS Suguba
    • NIMS, Tsukuba, Japan
    • National Cheng Kung University
    • 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
    • National Institute for Materials Science, International Center for Materials Nanoarchitectonics
    • National Institute of Material Science, Japan
    • Tsukuba, National Institute for Materials Science

  • Ilya Esterlis

    • Harvard University
    • Department of Physics, Harvard University

  • Eugene Demler

    • Harvard University
    • Department of Physics, Harvard University

  • Atac Imamoglu

    • ETH Zurich
    • Institute for Quantum Electronics, ETH Zurich
    • Physics, ETH Zurich