Synthesis of Intrinsic Magnetic Topological Insulator MnBi<sub>2n</sub>Te<sub>3n+1</sub> Family by Chemical Vapor Transport Method with Feedback Regulation.

Zhang, Heng; Zhang, Yiying; Zhang, Yong; Chen, Bo; Guo, Jingwen; Du, Yu; Li, Jiajun; Zhou, Fuwei et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

MnBi<sub>2n</sub>Te<sub>3n+1</sub> is a representative family of intrinsic magnetic topological insulators, in which numerous exotic phenomena such as the quantum anomalous Hall effect are expected. The high-quality crystal growth and magnetism manipulation are the most essential processes. Here a modified chemical vapor transport method using a feedback-regulated strategy is developed, which provides the closed-loop control of growth temperature within ± 0.1 °C. Single crystals of MnBi<sub>2</sub>Te<sub>4</sub>, MnBi<sub>4</sub>Te<sub>7</sub>, and MnBi<sub>6</sub>Te<sub>10</sub> are obtained under different temperature intervals respectively, and show variable tunability on magnetism by finely tuning the growth temperatures. Specifically, the cold-end temperatures not only vary the strength of antiferromagnetic coupling in MnBi<sub>2</sub>Te<sub>4</sub>, but also induce magnetic ground state transitions from antiferromagnetism to ferromagnetism in MnBi<sub>4</sub>Te<sub>7</sub> and MnBi<sub>6</sub>Te<sub>10</sub>. In MnBi<sub>2</sub>Te<sub>4</sub> with optimized magnetism, quantized transport with Chern insulator state can be easily replicated. These results provide a systematic picture for the crystal growth and the rich magnetic tunability of MnBi<sub>2n</sub>Te<sub>3n+1</sub> family, providing richer platforms for the related researches combining magnetism and topological physics.