Dynamic Polarization of Resident Electrons in WSe2 and WS2 Monolayers

ORAL

Abstract

We demonstrate very efficient spin-valley pumping of resident electrons in both WSe2 and WS2 mono- layers using circularly polarized light [1]. We use the degree of circular polarization of the photoluminescence (PL) associated with negative trions as probes of the polarization of resident electrons : both the intervalley triplet trion and the intravalley singlet trion which consist in the binding of a photo-generated electron-hole pair with a resident electron from the opposite and same valley respectively. In a charge adjustable WSe2 monolayer [2], we measure a very large positive PL circular polarization ~ 90% for the triplet trion and a negative polarization −40% for the singlet trion. This valley pumping also manifests as a large increase of the triplet trion PL intensity with circular excitation as compared to linear excitation. Interestingly, these results demonstrate that circularly polarized excitation photo-generates electron-hole pairs in one valley and dynamically polarize resident electrons in the opposite valley.  The spatial variation of the resident electron spin/valley polarization will also be discussed.

[1] C. Robert et al, Nature Com. 12, 5455 (2021)

[2] M. Yang et al, Arxiv 2110.00887 (2021)

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Publication: C. Robert et al, Nature Com. 12, 5455 (2021)
M. Yang et al, Arxiv 2110.00887 (2021)

Presenters

  • Xavier Marie

    • INSA University of Toulouse

Authors

  • Lei REN

    • Institut National des Sciences Appliquees de Toulouse

  • Cedric ROBERT

    • Institut National des Sciences Appliquees de Toulouse

  • Sangjun Park

    • Ecole Polytechnique - CNRS

  • Fabian Cadiz

    • Ecole Polytechnique - CNRS

  • laurent Lombez

    • Institut National des Sciences Appliquees de Toulouse

  • Alistair Rowe

    • Ecole Polytechnique

  • Daniel Paget

    • Ecole Polytechnique - CNRS

  • Fausto Sirotti

    • Laboratoire de Physique Matiere Condensee

  • Min Yang

    • University of Rochester

  • Dinh Van Thuan

    • University of Rochester

  • 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

  • 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

  • Bernhard Urbaszek

    • INSA University of Toulouse

  • Thierry Amand

    • Institut National des Sciences Appliquees de Toulouse

  • Hanan Dery

    • University of Rochester

  • Xavier Marie

    • INSA University of Toulouse