Pressure-Induced Topological and Structural Phase Transitions in an Antiferromagnetic Topological Insulator
Pressure-Induced Topological and Structural Phase Transitions in an Antiferromagnetic Topological Insulator
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DOI：
10.1088/0256-307x/37/6/066401
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发表时间：
2020-05
影响因子：
3.5
通讯作者：
Cuiying 翠颖 Pei 裴;Yunyouyou 云悠悠 Xia 夏;Jiazhen 家臻 Wu 邬;Y. Zhao 赵;Lingling 玲玲 Gao 高;Tianping 天平 Ying 应-
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文献类型：
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作者：
Cuiying 翠颖 Pei 裴;Yunyouyou 云悠悠 Xia 夏;Jiazhen 家臻 Wu 邬;Y. Zhao 赵;Lingling 玲玲 Gao 高;Tianping 天平 Ying 应-
最近，（MnBi2Te4）m(Bi2Te3)n的自然范德华异质结构已被理论预测和实验证明具有可调谐的磁性和拓扑非平凡的表面态。我们系统地研究了MnBi2Te4和MnBi4Te7对外部压力的结构和电子响应。除了抑制反铁磁有序外，MnBi2Te4在压缩时还经历了金属-半导体-金属的转变。MnBi4Te7的电阻率在高压下发生显著变化，ρ (T)呈非单调演化。证明了非平凡拓扑在高压状态下观察到的结构相变之前持续存在。我们发现体态和表面态对压力的响应不同，这与电阻率的非单调变化是一致的。有趣的是，在MnBi2Te4中观察到一个压力诱导的非晶态，而在MnBi4Te7中发现了两个高压相变。我们的理论和实验相结合的研究表明，MnBi2Te4和MnBi4Te7是高度可调谐的磁性拓扑绝缘体，在压缩时出现相变和新的基态。
Recently, natural van der Waals heterostructures of (MnBi2Te4)m(Bi2Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states. We systematically investigate both the structural and electronic responses of MnBi2Te4 and MnBi4Te7 to external pressure. In addition to the suppression of antiferromagnetic order, MnBi2Te4 is found to undergo a metal–semiconductor–metal transition upon compression. The resistivity of MnBi4Te7 changes dramatically under high pressure and a non-monotonic evolution of ρ (T) is observed. The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime. We find that the bulk and surface states respond differently to pressure, which is consistent with the non-monotonic change of the resistivity. Interestingly, a pressure-induced amorphous state is observed in MnBi2Te4, while two high-pressure phase transitions are revealed in MnBi4Te7. Our combined theoretical and experimental research establishes MnBi2Te4 and MnBi4Te7 as highly tunable magnetic topological insulators, in which phase transitions and new ground states emerge upon compression.