Observation of Quantum Anomalous Hall Effect and Exchange Interaction in Topological Insulator/Antiferromagnet Heterostructure

Journal Article · Tue Jul 21 00:00:00 EDT 2020 · Advanced Materials

DOI:https://doi.org/10.1002/adma.202001460· OSTI ID:1640256

Pan, Lei  ^[1]; Grutter, Alexander ^[2]; Zhang, Peng ^[1]; Che, Xiaoyu ^[1]; Nozaki, Tomohiro ^[3]; Stern, Alex ^[4]; Street, Mike ^[5]; Zhang, Bing ^[6]; Casas, Brian ^[4]; He, Qing Lin ^[7]; Choi, Eun Sang ^[8]; Disseler, Steven M. ^[2]; Gilbert, Dustin A. ^[9]; Yin, Gen ^[1]; Shao, Qiming ^[10]; Deng, Peng ^[1]; Wu, Yingying ^[1]; Liu, Xiaoyang ^[11]; Kou, Xufeng ^[11]; Masashi, Sahashi ^[3] ; Han, Xiaodong ^[6]; Binek, Christian ^[5]; Chambers, Scott ^[12]; Xia, Jing ^[4]; Wang, Kang L. ^[13]

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1. Department of Electrical and Computer Engineering University of California Los Angeles CA 90095 USA
2. NIST Center for Neutron Research National Institute of Standards and Technology Gaithersburg MD 20899‐6102 USA
3. Department of Electronic Engineering Tohoku University Sendai 980‐8579 Japan
4. Department of Physics and Astronomy University of California Irvine CA 92697 USA
5. Department of Physics and Astronomy University of Nebraska Lincoln NE 68588 USA
6. Beijing Key Lab of Microstructure and Property of Advanced Materials Beijing University of Technology Beijing 100124 China
7. Department of Electrical and Computer Engineering University of California Los Angeles CA 90095 USA, International Center for Quantum Materials School of Physics Peking University Beijing 100871 China
8. National High Magnetic Field Laboratory Florida State University Tallahassee FL 32310‐3706 USA
9. Department of Materials Science University of Tennessee Knoxville TN 37996 USA
10. Department of Electrical and Computer Engineering University of California Los Angeles CA 90095 USA, Department of Electronic and Computer Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong SAR China
11. School of Information Science and Technology ShanghaiTech University Shanghai 200031 China
12. Physical and Computational Sciences Directorate Pacific Northwest National Laboratory Richland WA 99352 USA
13. Department of Electrical and Computer Engineering University of California Los Angeles CA 90095 USA, Department of Materials Science and Engineering University of California Los Angeles CA 90095 USA, Department of Physics University of California Los Angeles CA 90095 USA

Abstract Integration of a quantum anomalous Hall insulator with a magnetically ordered material provides an additional degree of freedom through which the resulting exotic quantum states can be controlled. Here, an experimental observation is reported of the quantum anomalous Hall effect in a magnetically‐doped topological insulator grown on the antiferromagnetic insulator Cr ₂ O ₃ . The exchange coupling between the two materials is investigated using field‐cooling‐dependent magnetometry and polarized neutron reflectometry. Both techniques reveal strong interfacial interaction between the antiferromagnetic order of the Cr ₂ O ₃ and the magnetic topological insulator, manifested as an exchange bias when the sample is field‐cooled under an out‐of‐plane magnetic field, and an exchange spring‐like magnetic depth profile when the system is magnetized within the film plane. These results identify antiferromagnetic insulators as suitable candidates for the manipulation of magnetic and topological order in topological insulator films.

• Sponsoring Organization: USDOE
• OSTI ID: 1640256
• Journal Information: Advanced Materials, Journal Name: Advanced Materials Vol. 32 Journal Issue: 34; ISSN 0935-9648
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English