Topological kerr effects in two-dimensional magnets with broken inversion symmetry

ABSTRACT The whorls of localized moments in chiral magnetic structures, such as skyrmions, lead to a quantized topological charge, which may make them useful as next-generation information

bits. So far, the most reliable way to detect the existence of skyrmions is by using the topological Hall effect, which stems from electron scattering by the emergent magnetic field

manifesting the topological charge. Here we employ two-dimensional magnets to establish a magneto-optical hallmark of skyrmions, which we call the topological Kerr effect, using the recently

discovered ferromagnet CrVI6 as a material platform. The Kerr angle hysteresis loop of this non-centrosymmetric system exhibits two antisymmetric bumps that are absent in the

centrosymmetric CrI3 and VI3. We develop a minimal model to further identify the bumps as direct manifestations of the topological charge, thereby providing a magneto-optical fingerprint of

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support SIMILAR CONTENT BEING VIEWED BY OTHERS MULTISTEP TOPOLOGICAL TRANSITIONS AMONG MERON AND SKYRMION CRYSTALS IN A CENTROSYMMETRIC MAGNET Article 01 April 2024 TOPOLOGICAL ORBITAL HALL

EFFECT CAUSED BY SKYRMIONS AND ANTIFERROMAGNETIC SKYRMIONS Article Open access 11 January 2025 TOPOLOGICAL MAGNETO-OPTICAL EFFECT FROM SKYRMION LATTICE Article Open access 05 September 2023

DATA AVAILABILITY Source data are provided with this paper. All other data that support the plots within this paper and other findings of this study are available from the corresponding

author upon reasonable request. CODE AVAILABILITY The Spirit code and manual are available at https://spirit-code.github.io/. Codes for reproducing the simulation results are available from

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J. Wrachtrup, Q. Sun, Y. Zhang, Y. Wang, X. Wang and many other colleagues from their groups for various suggestions and efforts on potential direct detection of skyrmions in the newly

synthesized magnet of CrVI6. This work was supported by the National Natural Science Foundation of China (Grant Nos. 11574316, 11722435, 11804210, 11904350, 11974323, 12374458, U2032218,

12274276, 51627901 and U1932216), the Innovation Programme for Quantum Science and Technology (Grant No. 2021ZD0302800), the Strategic Priority Research Programme of Chinese Academy of

Sciences (CAS) (Grant No. XDB0510200), the Anhui Initiative in Quantum Information Technologies (Grant No. AHY170000), the Anhui Provincial Natural Science Foundation (Grant. No.

2008085QA30) and National Synchrotron Radiation Laboratory (KY2060000177). C.L. and Z.S. gratefully acknowledge financial support from the National Key R&D Programme of China (Grant Nos.

2021YFA1600200, 2017YFA0303603 and 2023YFA1607701), the Plan for Major Provincial Science & Technology Project (Grant No. 202003a05020018), the Key Research Programme of Frontier

Sciences, CAS (Grant No. QYZDB-SSW-SLH011), and the Users with Excellence Programme of Hefei Science Center, CAS (Grant No. 2021HSC-UE009). A portion of this work was performed on the Steady

High Magnetic Field Facilities, High Magnetic Field Laboratory, CAS, and supported by the High Magnetic Field Laboratory of Anhui Province. This research was also partially carried out at

the USTC Center for Micro and Nanoscale Research and Fabrication. AUTHOR INFORMATION Author notes * These authors contributed equally: Xiaoyin Li, Caixing Liu, Ying Zhang. AUTHORS AND

AFFILIATIONS * International Center for Quantum Design of Functional Materials (ICQD), and Hefei National Laboratory, University of Science and Technology of China, Hefei, China Xiaoyin Li, 

Shunhong Zhang, Dazhi Hou, Ping Cui & Zhenyu Zhang * High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, China Caixing Liu, Yuchen Zhang, Wenjie Meng, De Hou, 

Qingyou Lu & Zhigao Sheng * Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology,

University of Science and Technology of China, Hefei, China Ying Zhang, Fanyang Huang, Ruiguo Cao & Bin Xiang * Key Laboratory of Magnetic Molecules and Magnetic Information Materials

of the Ministry of Education and Research Institute of Materials Science, Shanxi Normal University, Taiyuan, China Huisheng Zhang & Xiaohong Xu * Hefei National Laboratory for Physical

Sciences at the Microscale and Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China Yuchen Zhang & Qingyou Lu * Center

for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Department of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an, China Tao

Li & Tai Min * Key Laboratory for Quantum Matters and Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng, China Chaoyang Kang & Weifeng Zhang * Department of

Physics, University of Science and Technology of China, Hefei, China Dazhi Hou * Institute of Quantum Materials and Physics, Henan Academy of Sciences, Zhengzhou, China Weifeng Zhang Authors

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CONTRIBUTIONS Z.Z. conceived the central idea and directed the project. H.Z., P.C., X.X. and Z.Z. predicted the CrVI6 monolayer as a new 2D magnet. X.L. and S.Z. performed theoretical

modelling and analysis. Ying Zhang synthesized the samples and fabricated the devices for MOKE measurements under supervision of B.X. F.H. and R.C. performed atomic-force-microscopy

characterization of the thickness of CrVI6 flakes. C.L. and De Hou performed MOKE measurements under supervision of Z.S. Yuchen Zhang and W.M. performed MFM imaging under supervision of Q.L.

T.L., T.M., C.K., W.Z. and X.X. performed various syntheses and characterizations of CrI3 and VI3 crystals, devised methods for protection of the CrVI6 samples at varying Cr/V ratios, and

carried out subsequent electrical transport measurements. Dazhi Hou contributed to the conceptual development. All authors contributed to the interpretation of the data. X.L., S.Z. and Z.Z.

wrote the paper with input from all the authors. CORRESPONDING AUTHORS Correspondence to Zhigao Sheng, Bin Xiang or Zhenyu Zhang. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare

no competing interests. PEER REVIEW PEER REVIEW INFORMATION _Nature Physics_ thanks the anonymous reviewer(s) for their contribution to the peer review of this work. ADDITIONAL INFORMATION

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Supplementary Methods, Tables 1–3, Notes 1–3, Figs. 1–13 and Refs. 1–10. SOURCE DATA SOURCE DATA FIG. 2 Measured and simulated XRD, magnetization-temperature data and magnetization

hysteresis loop of a CrVI6 flake. SOURCE DATA FIG. 3 Kerr rotation angle data of CrIV6 measured at different temperatures. SOURCE DATA FIG. 4 Magnetization hysteresis loop data from LLG

simulation; optical Hall conductivity and Kerr rotation angle hysteresis loops from tight-binding calculations; snapshot spin configurations from LLG simulations in Vector Field File Format

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permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Li, X., Liu, C., Zhang, Y. _et al._ Topological Kerr effects in two-dimensional magnets with broken inversion symmetry. _Nat. Phys._ 20,

1145–1151 (2024). https://doi.org/10.1038/s41567-024-02465-5 Download citation * Received: 14 January 2022 * Accepted: 05 March 2024 * Published: 04 April 2024 * Issue Date: July 2024 * DOI:

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