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arXiv · 2204.09950

Exchange bias in van der Waals MnBi$_2$Te$_4$/Cr$_2$Ge$_2$Te$_6$ heterostructure

Jing-Zhi Fang·Hao-Nan Cui·Shuo Wang·Jing-Di Lu·Xin-Jie Liu·Guang-Yu Zhu·Mao-Sen Qin·Jian-Kun Wang·Ze-Nan Wu·Yan-Fei Wu·Shou-Guo Wang·Zhongming Wei·Jinxing Zhang·Ben-Chuan Lin·Zhi-Min Liao·Dapeng Yu
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Abstract

The layered van der Waals (vdW) material MnBi$_2$Te$_4$ is an intrinsic magnetic topological insulator with various topological phases such as quantum anomalous Hall effect (QAHE) and axion states. However, both the zero-field and high-temperature QAHE are not easy to realize. It is theoretically proposed that the exchange bias can be introduced in the MnBi2Te4/ferromagnetic (FM) insulator heterostructures and thus opens the surface states gap, making it easier to realize the zero-field or high-temperature QAHE. Here we report the electrically tunable exchange bias in the van der Waals MnBi$_2$Te$_4$/Cr$_2$Ge$_2$Te$_6$ heterostructure. The exchange bias emerges over a critical magnetic field and reaches the maximum value near the magnetic band gap. Moreover, the exchange bias was experienced by the antiferromagnetic (AFM) MnBi$_2$Te$_4$ layer rather than the FM layer. Such van der Waals heterostructure provides a promising platform to study the novel exchange bias effect and explore the possible high-temperature QAHE.

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Jing-Zhi Fang, Hao-Nan Cui, Shuo Wang, Jing-Di Lu, Xin-Jie Liu, Guang-Yu Zhu, Mao-Sen Qin, Jian-Kun Wang, Ze-Nan Wu, Yan-Fei Wu, Shou-Guo Wang, Zhongming Wei, Jinxing Zhang, Ben-Chuan Lin, Zhi-Min Liao, Dapeng Yu. 2022-04-21. Exchange bias in van der Waals MnBi$_2$Te$_4$/Cr$_2$Ge$_2$Te$_6$ heterostructure. https://arxiv.org/abs/2204.09950

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