Bipolar Wigner crystals and valley-dependent exciton Umklapp scattering in monolayer WSe2

ORAL

Abstract

We observe exciton Umklapp scattering signatures of electron and hole Wigner crystals in monolayer WSe2; they exhibit melting temperatures of ~27K and ~22K, respectively. By introducing a magnetic field to lift the valley degeneracy, we observe markedly enhanced scattering between excitons and Wigner crystal when they occupy the same valley and band. Our theoretical calculations show that the valley-dependent Umklapp scattering arises from different exchange interactions between excitons and Wigner crystals in different valleys. Our research demonstrates intriguing interplay among Wigner crystals, excitons, and valleys in monolayer WSe2.

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Presenters

  • Matthew Wilson

    University of California, Riverside

Authors

  • Matthew Wilson

    University of California, Riverside

  • Erfu Liu

    Nanjing University

  • Tianyi Ouyang

    University of California, Riverside

  • 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

  • Yia-Chung Chang

    Research Center for Applied Sciences, Academia Sinica, Taipei, Sinica

  • Chun Hung Lui

    University of California, Riverside