Gate-tunable Intrinsic Anomalous Hall Effect in Epitaxial MnBi2Te4 Films

Shanshan Liu; Jie-Xiang Yu; Enze Zhang; Zihan Li; Qiang Sun; Yong Zhang; Liwei Cao; Lun Li; Minhao Zhao; Pengliang Leng; Xiangyu Cao; Ang Li; Jin Zou; Xufeng Kou; Jiadong Zang; Faxian Xiu

doi:10.1021/acs.nanolett.3c02926

Gate-tunable Intrinsic Anomalous Hall Effect in Epitaxial MnBi₂Te₄ Films

Nano Lett. 2024 Jan 10;24(1):16-25. doi: 10.1021/acs.nanolett.3c02926. Epub 2023 Dec 18.

Authors

Shanshan Liu^{1

2}, Jie-Xiang Yu³, Enze Zhang¹, Zihan Li^{1

2}, Qiang Sun^{4

5}, Yong Zhang⁶, Liwei Cao⁷, Lun Li⁶, Minhao Zhao^{1

2}, Pengliang Leng^{1

2}, Xiangyu Cao^{1

2}, Ang Li⁷, Jin Zou^{4

5}, Xufeng Kou⁶, Jiadong Zang⁸, Faxian Xiu^{1

2

9

10

11}

Affiliations

¹ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
² Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China.
³ School of Physical Science and Technology, Soochow University, Suzhou 215006, China.
⁴ Materials Engineering, The University of Queensland, Brisbane QLD 4072, Australia.
⁵ Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane QLD 4072, Australia.
⁶ School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China.
⁷ Beijing Key Lab of Microstructure and Property of Advanced Material, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
⁸ Department of Physics and Astronomy, University of New Hampshire, Durham, New Hampshire 03824, United States.
⁹ Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China.
¹⁰ Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China.
¹¹ Shanghai Research Center for Quantum Sciences, Shanghai 201315, China.

PMID: 38109350
DOI: 10.1021/acs.nanolett.3c02926

Abstract

The anomalous Hall effect (AHE) is an important transport signature revealing topological properties of magnetic materials and their spin textures. Recently, MnBi₂Te₄ has been demonstrated to be an intrinsic magnetic topological insulator. However, the origin of its intriguing AHE behaviors remains elusive. Here, we demonstrate the Berry curvature-dominated intrinsic AHE in wafer-scale MnBi₂Te₄ films. By applying back-gate voltages, we observe an ambipolar conduction and n-p transition in ∼7-layer MnBi₂Te₄, where a quadratic relation between the AHE resistance and longitudinal resistance suggests its intrinsic AHE nature. In particular, for ∼3-layer MnBi₂Te₄, the AHE sign can be tuned from pristine negative to positive. First-principles calculations unveil that such an AHE reversal originated from the competing Berry curvature between oppositely polarized spin-minority-dominated surface states and spin-majority-dominated inner bands. Our results shed light on the underlying physical mechanism of the intrinsic AHE and provide new perspectives for the unconventional sign-tunable AHE.

Keywords: AHE sign reversal; MnBi2Te4 thin film; anomalous Hall effect; gate-tunable; magnetic topological insulator.