Synthesis of Intrinsic Magnetic Topological Insulator MnBi2nTe3n+1 Family by Chemical Vapor Transport Method with Feedback Regulation
MnBi 2n Te 3n+1 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 2 Te 4 , MnBi 4 Te 7 , and MnBi 6 Te 10 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 2 Te 4 , but also induce magnetic ground state transitions from antiferromagnetism to ferromagnetism in MnBi 4 Te 7 and MnBi 6 Te 10 . In MnBi 2 Te 4 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 2n Te 3n+1 family, providing richer platforms for the related researches combining magnetism and topological physics.
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