Nie Xiao-Ang, Li Shujing, Yang Meng, Zhu Zhen, Xu Hao-Ke, Yang Xu, Zheng Fawei, Guan Dandan, Wang Shiyong, Li Yao-Yi, Liu Canhua, Li Jian, Zhang Ping, Shi Youguo, Zheng Hao, Jia Jinfeng
School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science , Shanghai Jiao Tong University , Shanghai 200240 , China.
College of Mathematics and Physics , Beijing University of Chemical Technology , Beijing 100029 , China.
ACS Nano. 2020 Feb 25;14(2):2366-2372. doi: 10.1021/acsnano.9b09564. Epub 2020 Feb 4.
A two-dimensional topological insulator features (only) one bulk gap with nontrivial topology, which protects one-dimensional boundary states at the Fermi level. We find a quantum phase of matter beyond this category: a multiple topological insulator. It possesses a ladder of topological gaps; each gap protects a robust edge state. We prove a monolayer of van der Waals material PtBi as a two-dimensional multiple topological insulator. By means of scanning tunneling spectroscopy, we directly visualize the one-dimensional hot electron (and hole) channels with nanometer size on the samples. Furthermore, we confirm the topological protection of these channels by directly demonstrating their robustness to variations of crystal orientation, edge geometry, and sample temperature. The discovered topological hot electron materials may be applied as efficient photocatalysts in the future.
二维拓扑绝缘体仅具有一个具有非平凡拓扑结构的体能隙，该体能隙保护费米能级处的一维边界态。我们发现了一种超越此类别的量子物态：多重拓扑绝缘体。它拥有一系列拓扑能隙；每个能隙都保护着一个稳健的边缘态。我们证明了范德华材料单层PtBi是一种二维多重拓扑绝缘体。通过扫描隧道光谱，我们直接在样品上可视化了纳米尺寸的一维热电子（和空穴）通道。此外，我们通过直接证明这些通道对晶体取向、边缘几何形状和样品温度变化的稳健性，证实了它们的拓扑保护特性。所发现的拓扑热电子材料未来可能会被用作高效光催化剂。
