Cui Yugui, Chu Yi, Pan Zhencun, Xing Yingjie, Huang Shaoyun, Xu Hongqi
Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics, Peking University, Beijing, 100871, P. R. China.
Nanoscale. 2021 Dec 16;13(48):20417-20424. doi: 10.1039/d1nr07047a.
SmB, which opens up an insulating bulk gap due to hybridization between itinerant d-electrons and localized f-electrons below a critical temperature, turns out to be a topological Kondo insulator possessing exotic conducting states on its surface. However, measurement of the surface-states in SmB draws controversial conclusions, depending on the growth methods and experimental techniques used. Herein, we report anisotropic magnetoresistance (AMR) observed in the Kondo energy gap of a single SmB nanowire that is immune to magnetic dopant pollution and features a square cross-section to show high-symmetry crystal facets. The AMR clearly shows a cosine function of included angle between magnetic field and measuring current with a period of π. The positive AMR is interpreted by anisotropically lifting the topological protection of spin-momentum inter-locking surface-states by rotating the in-plane magnetic field, which, therefore, provides the transport evidence that supports the topologically nontrivial nature of the SmB surface-states.
SmB在低于临界温度时，由于巡游d电子与局域f电子之间的杂化而打开一个绝缘体能隙，结果表明它是一种拓扑近藤绝缘体，其表面具有奇异的导电态。然而，根据所使用的生长方法和实验技术，对SmB表面态的测量得出了有争议的结论。在此，我们报告了在单个SmB纳米线的近藤能隙中观察到的各向异性磁阻（AMR），该纳米线不受磁性掺杂污染影响，且具有方形横截面以显示高对称晶面。AMR清楚地显示出磁场与测量电流之间夹角的余弦函数，周期为π。正的AMR被解释为通过旋转面内磁场各向异性地提升自旋动量互锁表面态的拓扑保护，因此，这提供了支持SmB表面态拓扑非平凡性质的输运证据。
