1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2].
1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China [2].
Nat Commun. 2013;4:3010. doi: 10.1038/ncomms4010.
SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states.
SmB6 是一种著名的近藤绝缘体，在低温下表现出输运异常。这种异常通常归因于杂化隙内的状态。最近的理论工作和输运测量表明，这些隙内态可能归因于拓扑表面态，这将使 SmB6 成为首个实现拓扑近藤绝缘体的材料。在这里，我们通过角分辨光电子能谱实验，直接观察到 SmB6 杂化隙内的几个色散态。这些态表现出可以忽略的 kz 依赖性，这表明它们具有表面起源。此外，我们进行了光电子圆二色性实验，表明隙内态具有轨道角动量的手性。这些态在大约 150 K 时与杂化隙一起同时消失。综上所述，这些观察结果表明隙内态可能具有拓扑起源。
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