Giant and nonreciprocal second harmonic generation from layered antiferromagnetism in bilayer CrI<sub>3</sub>

ORAL

Abstract

Layered antiferromagnetism is the spatial arrangement of ferromagnetic layers with antiferromagnetic interlayer coupling. Recently, the van der Waals magnet, chromium triiodide (CrI3), emerged as the first layered antiferromagnetic insulator in its few-layer form. In this talk, we present an emergent nonreciprocal second-order nonlinear optical effect in bilayer CrI3. The observed second-harmonic generation (SHG) is giant: several orders of magnitude larger than known magnetization induced SHG and comparable to SHG in the best 2D nonlinear optical materials studied so far. We show that while the parent lattice of bilayer CrI3 is centrosymmetric and thus does not contribute to the SHG signal, the observed nonreciprocal SHG originates purely from the layered antiferromagnetic order, which breaks both spatial inversion and time reversal symmetries. Furthermore, polarization-resolved measurements reveal the underlying C2h symmetry, and thus monoclinic stacking order in CrI3 bilayers, providing key structural information for the microscopic origin of layered antiferromagnetism. Our results indicate that SHG is a highly sensitive probe of subtle magnetic orders and open up possibilities for the use of two-dimensional magnets in nonlinear and nonreciprocal optical devices.

Presenters

  • Zeyuan Sun

    • Fudan University

Authors

  • Zeyuan Sun

    • Fudan University

  • Yangfan Yi

    • Fudan University

  • Tiancheng Song

    • University of Washington

  • Genevieve Clark

    • University of Washington

  • Bevin Huang

    • University of Washington
    • Physics, University of Washington

  • Yuwei Shan

    • Fudan University

  • Shuang Wu

    • Fudan University

  • Di Huang

    • Department of Physics, Fudan University
    • Fudan University

  • Chunlei Gao

    • Fudan University

  • Zhanghai Chen

    • Fudan University

  • Michael McGuire

    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Materials Science Division, Oak Ridge National Laboratory

  • Ting Cao

    • University of Washington
    • Department of Physics, University of California at Berkeley and Lawrence Berkeley National Laboratory
    • Physics, University of Washington
    • Department of Materials Science and Engineering, University of Washington and Geballe Laboratory for Advanced Materials, Stanford University

  • Di Xiao

    • Physics, Carnegie Mellon University
    • Carnegie Mellon University
    • Carnegie Mellon Univ
    • Department of Physics, Carnegie Mellon University

  • Wei-Tao Liu

    • Fudan University

  • Wang Yao

    • University of Hong Kong
    • The University of Hong Kong
    • Department of Physics and Centre of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China

  • Xiaodong Xu

    • University of Washington
    • Physics, University of Washington

  • Shiwei Wu

    • Department of Physics, Fudan University
    • Fudan University
    • Fudan Univ