Control moiré magnetic moment interactions by light polarizations

ORAL

Abstract

The ability of controlling many-body interactions between carriers is essential to explore correlated phenomena and access complex electronic phase diagram. Transition metal dichalcogenide (TMD) moiré superlattice emerges to be a powerful platform for studying correlated physics due to its highly tunable many-body Hamiltonian. Recently, a non-equilibrium, light induced ferromagnetic states was observed in WSe2/WS2 heterobilayers, pointing to dynamic optical control of electron correlations. Here we report light polarization controlled magnetic interactions between localized moments in WSe2/WS2 moiré superlattices. Using a continuous-wave pump-probe reflective magnetic circular dichroism (RMCD) measurements, we show that ferromagnetic states can be induced by linearly polarized pump, i.e., no optical orientation of carrier spins are needed. However, under circularly polarized pump, we find that the RMCD response is drastically enhanced at low excitation regime, and near completely suppressed when the photo-excited exciton-spin density is comparable to moiré cell density. Our results reveal a collaboration-competition relation between excitons mediated spin-spin interaction and valley-pseudo magnetic field effect in the formation of ferromagnetic states.

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Presenters

  • Jiayi Zhu

    • University of Washington

Authors

  • Jiayi Zhu

    • University of Washington

  • Heonjoon Park

    • University of Washington

  • Chengxin Xiao

    • The University of Hong Kong

  • Xi Wang

    • University of Washington

  • Kyle Hwangbo

    • University of Washington

  • Takashi Taniguchi

    • National Institute for Materials Science
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute of Materials Science
    • Kyoto University
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute For Materials Science
    • NIMS
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Kenji Watanabe

    • National Institute for Materials Science
    • Research Center for Functional Materials, National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Jiaqiang Yan

    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

  • Daniel R Gamelin

    • University of Washington

  • Wang Yao

    • The University of Hong Kong

  • Xiaodong Xu

    • University of Washington