Interlayer excitons in bilayer MoS2 with strong oscillator strength up to room temperature

ORAL

Abstract

Coulomb bound electron-hole pairs, excitons, govern the optical properties of transition metal dichalcogenides (TMDs) like MoS2 and WSe2. TMD bilayers allow studying several exciton species : intralayer excitons with electrons and holes in the same layer and also interlayer excitons with the electron and the hole residing in different layers.
In this combined experimental and theoretical work we report on the observation of interlayer excitons in a high quality homobilayer MoS2 sample encapsulated in hexagonal boron nitride (hBN). The interlayer exciton transition is located between the intralayer A and B excitons and is observable in reflectivity between 4 and 300 K, whereas no such transition is observed for the monolayer in the same structure in this energy range. Our peak attribution is supported by DFT calculations solving the Bethe-Salpeter equation after GW bandstructure calculations. We find in the calculated absorption spectrum a strong, spin allowed transition situated in energy between A and B intralayer excitons stemming from an electron residing on one and the hole residing in the other layer, both at the K-point of the Brillouin zone. We discuss the possibility of hybridization of exciton species and compare with our results on homotrilayer MoS2.

*ANR 2D-vdW-spin

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Presenters

  • Bernhard Urbaszek

    • CNRS/INSA
    • LPCNO, Institut National des Sciences Appliquees de Toulouse
    • INSA/CNRS
    • INSA Toulouse

Authors

  • Bernhard Urbaszek

    • CNRS/INSA
    • LPCNO, Institut National des Sciences Appliquees de Toulouse
    • INSA/CNRS
    • INSA Toulouse

  • Iann Gerber

    • LPCNO, Institut National des Sciences Appliquées de Toulouse
    • CNRS/INSA

  • Emmanuel Courtade

    • INSA/CNRS
    • INSA Toulouse
    • CNRS/INSA

  • Shivangi Shree

    • INSA/CNRS
    • CNRS/INSA

  • Cedric Robert

    • INSA Toulouse
    • CNRS/INSA

  • Xavier Marie

    • CNRS/INSA
    • LPCNO, Institut National des Sciences Appliquees de Toulouse
    • LPCNO, Institut National des Sciences Appliquées de Toulouse
    • INSA/CNRS
    • INSA Toulouse

  • Kenji Watanabe

    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305 0044, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science, , 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044
    • National Institute of Materials Science
    • NIMS, Japan
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science (NIMS)
    • NIMS Tsukuba
    • National Institute for Materials Science (Japan)
    • NIMS
    • National Institute for Material Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
    • National Institute for Materials Science , Japan
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan.
    • Advanced Materials Laboratory, National Institute for Materials Science, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan
    • National Institute for Material Science - Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • National Institute of Material Science
    • Advanced Material Lab, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • National Institute for Materials Science, Tsukuba
    • 1-1 Namiki, Tsukuba, National Institute for Materials Science
    • NIMS/Tsukuba
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
    • National Institute for Materials Science, Namiki, 305-0044, Japan
    • National Institute for Material Science, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • Columbia University
    • Advanced Materials Labaratory, National Institute for Materials Science
    • National Institute of Material Science, 1-1 Namiki, Tsukuba, Ibaraki 205-0044, Japan
    • National Institute of Materials Science, Japan

  • Takashi Taniguchi

    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305 0044, Japan
    • National Institute for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science, , 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044
    • National Institute of Materials Science
    • NIMS, Japan
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Tsukuba, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science (NIMS)
    • NIMS Tsukuba
    • NIMS
    • National Institute for Material Science
    • National Institute for Materials Science, Japan
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
    • National Institute for Materials Science , Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan
    • National Institute for Material Science - Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • National Institute of Material Science
    • Advanced Material Lab, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • National Institute for Materials Science, Tsukuba
    • 1-1 Namiki, Tsukuba, National Institute for Materials Science
    • NIMS/Tsukuba
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
    • National Institute for Materials Science, Namiki, 305-0044, Japan
    • National Institute for Material Science, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • Advanced Materials Labaratory, National Institute for Materials Science
    • National Institute of Material Science, 1-1 Namiki, Tsukuba, Ibaraki 205-0044, Japan
    • National Institute of Materials Science, Japan