Gu Mingqiang, Li Jiayu, Sun Hongyi, Zhao Yufei, Liu Chang, Liu Jianpeng, Lu Haizhou, Liu Qihang
Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.
Nat Commun. 2021 Jun 10;12(1):3524. doi: 10.1038/s41467-021-23844-z.
The topological surface states of magnetic topological systems, such as Weyl semimetals and axion insulators, are associated with unconventional transport properties such as nonzero or half-quantized surface anomalous Hall effect. Here we study the surface anomalous Hall effect and its spectral signatures in different magnetic topological phases using both model Hamiltonian and first-principles calculations. We demonstrate that by tailoring the magnetization and interlayer electron hopping, a rich three-dimensional topological phase diagram can be established, including three types of topologically distinct insulating phases bridged by Weyl semimetals, and can be directly mapped to realistic materials such as MnBiTe/(BiTe) systems. Among them, we find that the surface anomalous Hall conductivity in the axion-insulator phase is a well-localized quantity either saturated at or oscillating around e/2h, depending on the magnetic homogeneity. We also discuss the resultant chiral hinge modes embedded inside the side surface bands as the potential experimental signatures for transport measurements. Our study is a significant step forward towards the direct realization of the long-sought axion insulators in realistic material systems.
诸如外尔半金属和轴子绝缘体等磁性拓扑系统的拓扑表面态，与非传统输运性质相关联，比如非零或半量子化的表面反常霍尔效应。在此，我们使用模型哈密顿量和第一性原理计算，研究了不同磁性拓扑相中的表面反常霍尔效应及其光谱特征。我们证明，通过调整磁化强度和层间电子跳跃，可以建立一个丰富的三维拓扑相图，其中包括由外尔半金属连接的三种拓扑不同的绝缘相，并且可以直接映射到诸如MnBiTe/(BiTe)系统这样的实际材料上。其中，我们发现轴子绝缘体相中的表面反常霍尔电导率是一个局域性良好的量，它要么饱和于e/2h，要么围绕e/2h振荡，这取决于磁均匀性。我们还讨论了作为输运测量潜在实验特征的、嵌入侧面能带内部的手性棱边模式。我们的研究朝着在实际材料系统中直接实现长期以来寻求的轴子绝缘体迈出了重要一步。
