Title: Giant nonreciprocal second-harmonic generation from antiferromagnetic bilayer CrI₃

Abstract

Layered antiferromagnetism is the spatial arrangement of ferromagnetic layers with antiferromagnetic interlayer coupling. The van der Waals magnet chromium triiodide (CrI₃) has been shown to be a layered antiferromagnetic insulator in its few-layer form, opening up opportunities for various functionalities in electronic and optical devices. Here we report an emergent nonreciprocal second-order nonlinear optical effect in bilayer CrI₃. The observed second-harmonic generation (SHG; a nonlinear optical process that converts two photons of the same frequency into one photon of twice the fundamental frequency) is several orders of magnitude larger than known magnetization-induced SHG and comparable to the SHG of the best (in terms of nonlinear susceptibility) two-dimensional nonlinear optical materials studied so far (for example, molybdenum disulfide). We show that although the parent lattice of bilayer CrI₃ is centrosymmetric, and thus does not contribute to the SHG signal, the observed giant nonreciprocal SHG originates only from the layered antiferromagnetic order, which breaks both the spatial-inversion symmetry and the time-reversal symmetry. Furthermore, polarization-resolved measurements reveal underlying C_2h crystallographic symmetry—and thus monoclinic stacking order—in bilayer CrI₃, providing key structural information for the microscopic origin of layered antiferromagnetism. Finally, our results indicate that SHG is a highly sensitive probe of subtle magnetic ordersmore » and open up possibilities for the use of two-dimensional magnets in nonlinear and nonreciprocal optical devices.« less

Authors:

Sun, Zeyuan ^[1]; Yi, Yangfan ^[1]; Song, Tiancheng ^[2]; Clark, Genevieve ^[2]; Huang, Bevin ^[2]; Shan, Yuwei ^[1]; Wu, Shuang ^[1]; Huang, Di ^[1]; Gao, Chunlei ^[3]; Chen, Zhanghai ^[3]; McGuire, Michael A.  ^[4];

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Cao, Ting ^[5]; Xiao, Di ^[6]; Tao Liu, Wei ^[3]; Yao, Wang ^[7]; Xu, Xiaodong ^[2]; Wu, Shiwei ^[3]

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+ Show Author Affiliations

1. Fudan Univ., Shanghai (China)
2. Univ. of Washington, Seattle, WA (United States)
3. Fudan Univ., Shanghai (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing (China)
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
5. Univ. of Washington, Seattle, WA (United States); Stanford Univ., CA (United States)
6. Carnegie Mellon Univ. (CMU), Pittsburgh, PA (United States)
7. Univ. of Hong Kong (China)

Publication Date:

2019-07-31

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; National Natural Science Foundation of China (NSFC); National Basic Research Program of China; National Key Research and Development Program of China; National Science Foundation (NSF)

OSTI Identifier:

1649491

Grant/Contract Number:  

AC05-00OR22725; 11427902; 2014CB921601; 2016YFA0301002; SC0012509; NSF-DMR-1708419; 17303518P; 11622429

Resource Type:

Accepted Manuscript

Journal Name:

Nature (London)

Additional Journal Information:

Journal Name: Nature (London); Journal Volume: 572; Journal Issue: 7770; Journal ID: ISSN 0028-0836

Publisher:

Nature Publishing Group

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; magnetic properties and materials; nonlinear optics; two-dimensional materials