CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai 200050, China.
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Nano Lett. 2023 Mar 8;23(5):1652-1658. doi: 10.1021/acs.nanolett.2c03773. Epub 2023 Feb 15.
The intrinsic antiferromagnetic topological insulator (TI) MnBiTe provides a capacious playground for the realization of topological quantum phenomena, such as the axion insulator states and quantum anomalous Hall (QAH) effect. In addition to nontrivial band topology, magnetism is another necessary ingredient for realizing these quantum phenomena. Here, we investigate signatures of thickness-dependent magnetism in exfoliated MnBiTe thin flakes. We observe an obvious odd-even layer-number effect in few-layer MnBiTe. Noticeably, we show that in monolayer MnBiTe the anomalous Hall effect exhibits a sign reversal. Compared with the case of MnBiTe, interlayer antiferromagnetic exchange coupling, which is essential for the realization of the QAH effect, is greatly suppressed in MnBiTe. The demonstration of thickness-dependent magnetic properties is helpful to further explore the topological quantum phenomena in MnBiTe.
本征反铁磁拓扑绝缘体 (TI) MnBiTe 为实现拓扑量子现象提供了广阔的平台，例如轴子绝缘体态和量子反常霍尔 (QAH) 效应。除了非平凡的能带拓扑，磁性是实现这些量子现象的另一个必要条件。在这里，我们研究了在剥离的 MnBiTe 薄膜中厚度相关磁性的特征。我们在少层 MnBiTe 中观察到明显的奇偶层数效应。值得注意的是，我们表明在单层 MnBiTe 中反常霍尔效应表现出符号反转。与 MnBiTe 的情况相比，对于实现 QAH 效应至关重要的层间反铁磁交换耦合在 MnBiTe 中受到很大抑制。对厚度相关磁性的证明有助于进一步探索 MnBiTe 中的拓扑量子现象。
