Higher-Order Topology in Bismuth.
Higher-Order Topology in Bismuth.
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DOI：
10.1038/s41567-018-0224-7
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发表时间：
2018-09-01
期刊：
影响因子：
19.6
通讯作者：
Neupert T
中科院分区：
文献类型：
--
作者：
Schindler F;Wang Z;Vergniory MG;Cook AM;Murani A;Sengupta S;Kasumov AY;Deblock R;Jeon S;Drozdov I;Bouchiat H;Guéron S;Yazdani A;Bernevig BA;Neupert T
拓扑学的数学领域已经成为描述晶体固体低能电子结构的框架。体绝缘三维拓扑晶体的典型特征是导电的二维表面态。这构成拓扑体边界对应。在这里，我们建立了铋的电子结构，一个元素一贯被描述为散装拓扑平凡，实际上是拓扑的，并遵循一个广义的散装边界对应的高阶：而不是表面的晶体，但其铰链主机拓扑保护的导电模式。这些铰链模式的保护本地化的时间反演对称性，并在全球范围内的三重旋转对称性和反演对称性的铋晶体。我们从理论上和实验上支持我们的主张。我们的理论分析是基于对称性参数，拓扑指数，第一性原理计算，以及最近引入的拓扑量子化学框架。我们提供了两个互补的实验技术的支持证据。利用扫描隧道光谱，我们探测了位于晶体表面台阶边缘的一维态的旋转对称性的独特特征。利用约瑟夫森干涉法，我们证明了它们对电子输运的普遍拓扑贡献。我们的工作建立铋作为一个高阶拓扑绝缘体。
The mathematical field of topology has become a framework to describe the low-energy electronic structure of crystalline solids. A typical feature of a bulk insulating three-dimensional topological crystal are conducting two-dimensional surface states. This constitutes the topological bulk-boundary correspondence. Here, we establish that the electronic structure of bismuth, an element consistently described as bulk topologically trivial, is in fact topological and follows a generalized bulk-boundary correspondence of higher-order: not the surfaces of the crystal, but its hinges host topologically protected conducting modes. These hinge modes are protected against localization by time-reversal symmetry locally, and globally by the three-fold rotational symmetry and inversion symmetry of the bismuth crystal. We support our claim theoretically and experimentally. Our theoretical analysis is based on symmetry arguments, topological indices, first-principle calculations, and the recently introduced framework of topological quantum chemistry. We provide supporting evidence from two complementary experimental techniques. With scanning-tunneling spectroscopy, we probe the unique signatures of the rotational symmetry of the one-dimensional states located at step edges of the crystal surface. With Josephson interferometry, we demonstrate their universal topological contribution to the electronic transport. Our work establishes bismuth as a higher-order topological insulator.
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影响因子：
56.9
作者：
Bernevig, B. Andrei;Hughes, Taylor L.;Zhang, Shou-Cheng
通讯作者：
Zhang, Shou-Cheng
影响因子：
3.7
作者：
Hobbs, D;Kresse, G;Hafner, J
通讯作者：
Hafner, J
影响因子：
19.6
作者：
Drozdov, Ilya K.;Alexandradinata, A.;Yazdani, Ali
通讯作者：
Yazdani, Ali
影响因子：
8.6
作者：
Bernevig, BA;Zhang, SC
通讯作者：
Zhang, SC
影响因子：
3.7
作者：
Geier, Max;Trifunovic, Luka;Brouwer, Piet W.
通讯作者：
Brouwer, Piet W.