Direct Observation of Gate-Tunable Dark Trions in Monolayer WSe<sub>2</sub>

ORAL

Abstract

Spin-forbidden intravalley dark excitons in tungsten-based transition-metal dichalcogenides (TMDCs) have attracted intense research interest. It has been discovered that tungsten-based TMDCs such as WSe2 and WS2 have a unique bandstructure, in which the spin-orbit coupling also induces the splitting of the conduction band. The resulted ground state of the exciton, however, is a spin-triplet state as the spin-forbidden dark exciton. We show that we can control the dark exciton electrostatically by dressing it with one free electron or free hole, forming the dark trions. The existence of the dark trions is suggested by the unique magneto-photoluminescence spectroscopy pattern of the monolayer WSe2 device. And the existence of the dark trions is unambiguously demonstrated by directly resolving the radiation angle of the dark trions through back focal plane imaging. The dark trions possess binding energy of ∼15 meV, and inherit the long lifetime and large g-factor from the dark exciton. The dark trions open the door to new possibilities of valleytronics and excitonic applications.

*We thank Dr. Lei Shi and Shengnan Miao for helpful discussions. We acknowledge support from AFOSR, through Grant No. FA9550-18-1-0312. and support from ACS PRF, through Grant No. 59957-DNI10.

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Presenters

  • Tianmeng Wang

    • Rensselaer Polytechnic Institute

Authors

  • Tianmeng Wang

    • Rensselaer Polytechnic Institute

  • Zhipeng Li

    • Rensselaer Polytechnic Institute

  • Zhengguang Lu

    • Natl High Magnetic Field Lab
    • National High Magnetic Field Laboratory

  • Mandeep Khatoniar

    • The City College of New York

  • zhen lian

    • Rensselaer Polytechnic Institute

  • Yuze Meng

    • Nanjing University

  • Mark Blei

    • Arizona State University
    • Materials Science and Engineering, Arizona State University

  • Takashi Taniguchi

    • National Institute for Materials Science, Japan
    • National Institute for Material Science
    • National Institute for Materials Science
    • National Institute for Materials Science, Tsukuba
    • Research Center for Functional Materials, NIMS
    • nims
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS
    • National Institute for Material Science - Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute for Materials Science (NIMS)
    • National Institute for Materials Science,Tsukuba, Ibaraki 305-0047, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Materials Science
    • National Institute for Materials Science, University of Tsukuba
    • National Institute for Materials Science, Tsukuba, Japan
    • National Institue for Material Science, Tsukuba
    • Advanced Materials Laboratory, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • Advanced Matrials Lab, NIMS
    • National Institute for Material Science, Tsukuba, Japan
    • National institute for materials science
    • NIMS-Tsukuba
    • NIMS, Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Advanced Materials Laboratory, National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science (Japan)
    • Physics, NIMS
    • National Institute of Materials Science, Japan
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • NIMS - Tsukuba

  • Kenji Watanabe

    • National Institute for Materials Science, Japan
    • National Institute for Material Science
    • National Institute for Materials Science
    • National Institute for Materials Science, Tsukuba
    • Research Center for Functional Materials, NIMS
    • nims
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS
    • National Institute for Material Science - Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute for Materials Science (NIMS)
    • National Institute for Materials Science,Tsukuba, Ibaraki 305-0047, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Materials Science
    • National Institute for Materials Science, University of Tsukuba
    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Material Science, Japan
    • National Institue for Material Science, Tsukuba
    • Advanced Materials Laboratory, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • Advanced Matrials Lab, NIMS
    • National Institute for Material Science, Tsukuba, Japan
    • National institute for materials science
    • NIMS-Tsukuba
    • NIMS, Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • NIRM
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Advanced Materials Laboratory, National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute of Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science (Japan)
    • Physics, NIMS
    • National Institute of Materials Science, Japan
    • National Institute of Materials Science (NIMS)
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • NIMS - Tsukuba

  • Stephen A McGill

    • National High Magnetic Field Laboratory
    • NHMFL, Florida
    • Natl High Magnetic Field Lab
    • National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
    • Physics, Florida State University
    • Florida State University, Tallahassee, FL 32310, USA, National High Magnetic Field Lab

  • Sefaattin Tongay

    • Arizona State University
    • Materials Science and Engineering, Arizona State University

  • Vinod M Menon

    • Physics, The City College of New York
    • The City College of New York

  • Dmitry Smirnov

    • Natl High Magnetic Field Lab
    • National High Magnetic Field Laboratory, Tallahassee, FL
    • National High Magnetic Field Lab
    • National High Magnetic Field Laboratory
    • national high magnetic field laboratory

  • Sufei Shi

    • Rensselaer Polytechnic Institute