Interlayer coupling modulated tunable magnetic states in superlattice MnBi2⁢Te4(Bi2⁢Te3)𝑛 topological insulators

Phys. Rev. B 109, 165410 (2024)

Jianfeng Guo, Huan Wang, Haoyan Zhang, Shuo Mi, Songyang Li, Haoyu Dong, Shiyu Zhu, Jiawei Hu, Xueyun Wang, Yanjun Li, Yasuhiro Sugawara, Rui Xu, Fei Pang, Wei Ji, Tianlong Xia, and Zhihai Cheng

Abstract:

The intrinsic superlattice magnetic topological insulators of MnBi2⁢Te4(Bi2⁢Te3)𝑛 (𝑛=0,1,2…) provides a promising material platform for the realization of diverse exotic topological quantum states, such as quantum anomalous Hall effect and axion-insulator state. All these quantum states are sensitively dependent on the complex interplay and intertwinement of their band topology, magnetism, and defective structural details. Here, we report a comprehensive real-space investigation on the magnetic ordering states of MnBi2⁢Te4(Bi2⁢Te3)𝑛 using cryogenic magnetic force microscopy. The MnBi2⁢Te4(Bi2⁢Te3)𝑛 crystals exhibit a distinctive magnetic evolution from A-type antiferromagnetic to ferromagnetic states via the increased Bi2⁢Te3 intercalation layers. The magnetic field- and temperature-dependent phase evolution behaviors of MnBi6⁢Te10 and MnBi8⁢Te13 are comparatively investigated to obtain the complete 𝐻−𝑇 phase diagrams. The combination impact of the intrinsic and defect-mediated interlayer coupling on their magnetic states were further discussed. Our results pave a possible way to realize more exotic quantum states via the tunable magnetic configurations in the artificial-stacking MnBi2⁢Te4(Bi2⁢Te3)𝑛 multilayers.

DOI: 10.1103/PhysRevB.109.165410

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