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Trends in wavefunction overlap, moiré-patterns and lattice reconstruction studied by interlayer exciton absorption spectroscopy

ORAL

Abstract

Interlayer excitons (ILXs), correlated electron-hole pairs split across two vertically stacked semiconducting monolayers, are strongly tunable through electrical field and through twist-angle [1,2,3]. While absorption measurements remain a robust exciton characterization tool, due to the weak oscillator strength of ILXs, to date most ILX characterization has focused on the photoluminescence measurements. Unfortunately, the photoluminescence data can be strongly modified by small strains and defects. Here, we present the ILX absorption spectra for the WSe2/MoSe2 heterostructure obtained using an electromodulation technique for samples at different twist-angles and under out-of-plane electric fields. These measurements have allowed us to extract intrinsic radiative lifetimes of ILXs in a robust manner. Looking at their electric field dependence, we obtain a signature of changing electron-hole wavefunction-overlap. In examining the oscillator strength of the ILX for different twist-angles, we find evidence both of a deep moiré potential and of reconstruction of the two materials for small twist angles.

References: [1] A. Jauregui et al., Science 366 (2019). [2] Rivera et al. Nat. Nanotech. (2018) [3] Choi et al. PRL. (2021)

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Presenters

  • Elyse Barre

    Stanford Univ, Stanford University

Authors

  • Elyse Barre

    Stanford Univ, Stanford University

  • Ouri Karni

    Stanford Univ

  • Erfu Liu

    University of California, Riverside

  • Aidan O'Beirne

    Stanford Univ

  • Henrique B Ribeiro

    Stanford University

  • Leo Yu

    Stanford University

  • Bumho Kim

    Columbia University

  • Kenji Watanabe

    National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science, NIMS, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 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 Institute for Materials Science, Advanced, Materials Laboratory, NIMS, 3 National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Materials Science, Tsukuba, Japan, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute for Materials Science (Japan), National Institute for Materials Science, Japan, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan, Research Center for Functional Materials, National Institute for Materials Science, Japan, Research Center for Functional Materials, National Institute for Materials Science, 1-1Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, Japan, National Institute for Material Science, National Institute of Material Sciences, Japan, NIMS, Tsukuba, 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan., National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science Japan, NIMS, Japan, nims, National Institute for Materials Science, Research Center for Functional Materials, Japan, National Institute for Materials Science Tsukuba, National Institute for Materials Science, 1-1 Namiki, National Institute for Materials Science of Japan, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, NIMS - National Institute for Material Science, Japan, Research Center for Functional Materials, National Institute for Material Science, Tsukuba, Ibaraki, 305-0044, Japan., National Institute for Material Science, Tsukuba, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science (NIMS), National Institute for Materials Science, Research Center for Functional Materials, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Material Science, Kyoto Univ, National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Takashi Taniguchi

    National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science, NIMS, Kyoto Univ, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Ibaraki 305-0044, Japan., 3 National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Materials Science, Tsukuba, Japan, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute for Materials Science (Japan), International Center for Materials Nanoarchitectonics, National Institute for Materials Science, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Kyoto University, International Center for Materials Nanoarchitectonics, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Japan, International Center for Materials Nanoarchitectonics, National Institute for MaterialsScience, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, Japan, National Institute for Material Science, National Institute of Material Sciences, Japan, NIMS, Tsukuba, 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan., National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science, Japan, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan., NIMS, Japan, National Institute for Materials Science (NIMS), NIMS. Japan, International Center for Material Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, International Center for Material Nanoarchitectonics, National Institute for Materials Science, National Institute for Materials Science Tsukuba, National Institute for Materials Science, 1-1 Namiki, National Institute for Materials Science of Japan, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, NIMS - National Institute for Material Science, Japan, International Center for Materials Nanoarchitectonics, National Institute for Material Science, Tsukuba, Ibaraki 305-0044, Japan., National Institute for Material Science, Tsukuba, National Institute for Materials Science, International Center for Materials Nanoarchitectonics, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Material Science, National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Katayun Barmak

    Columbia Univ, Columbia University

  • Chun Hung Lui

    University of California, Riverside, Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA.

  • Sivan Refaely-Abramson

    Weizmann Institute of Science

  • Felipe H da Jornada

    Stanford Univ, Stanford University

  • Tony F Heinz

    Stanford University