Wu Yanzhao, Deng Li, Tong Junwei, Yin Xiang, Qin Gaowu, Zhang Xianmin
Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, China.
Department of Physics, Freie Universität Berlin, Berlin 14195, Germany.
ACS Appl Mater Interfaces. 2024 Aug 7;16(31):41371-41378. doi: 10.1021/acsami.4c09774. Epub 2024 Jul 24.
The emergence of an intrinsic quantum anomalous Hall (QAH) insulator with long-range magnetic order triggers unprecedented prosperity for combining topology and magnetism in low dimensions. Here, based on stacked two-dimensional LiFeTe, we confirm that magnetic coupling and topological electronic states can be simultaneously manipulated by just changing the layer numbers. Monolayer LiFeTe shows intralayer ferrimagnetic coupling, behaving as a QAH insulator with Chern number = 2. Beyond the monolayer, the odd and even layers of LiFeTe correspond to uncompensated and compensated interlayer antiferromagnets, resulting in unexpected QAH and quantum spin Hall (QSH) states, respectively. Moreover, the spin Chern number is proportional to the stacking layer numbers in even-layer LiFeTe, proving that the spin Hall conductivity can be continuously enhanced by increasing layer numbers. Therefore, the odd-even-layer-dependent QAH and QSH effects found in LiFeTe topological insulators offer new insight into regulating quantum states in two-dimensional topological materials.
具有长程磁序的本征量子反常霍尔（QAH）绝缘体的出现，引发了低维拓扑与磁性相结合的前所未有的繁荣。在此，基于堆叠的二维LiFeTe，我们证实仅通过改变层数就可以同时操纵磁耦合和拓扑电子态。单层LiFeTe表现出层内亚铁磁耦合，是具有陈数 = 2的QAH绝缘体。除单层外，LiFeTe的奇数层和偶数层分别对应未补偿和补偿的层间反铁磁体，分别导致意想不到的QAH和量子自旋霍尔（QSH）态。此外，自旋陈数与偶数层LiFeTe中的堆叠层数成正比，证明自旋霍尔电导率可以通过增加层数而连续增强。因此，在LiFeTe拓扑绝缘体中发现的奇偶层依赖的QAH和QSH效应为调控二维拓扑材料中的量子态提供了新的见解。
