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Higher-Order Topology in Bismuth.

ABSTRACT: 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.

SUBMITTER: Schindler F

PROVIDER: S-EPMC6195185 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

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Higher-Order Topology in Bismuth.

Schindler Frank F Wang Zhijun Z Vergniory Maia G MG Cook Ashley M AM Murani Anil A Sengupta Shamashis S Kasumov Alik Yu AY Deblock Richard R Jeon Sangjun S Drozdov Ilya I Bouchiat Hélène H Guéron Sophie S Yazdani Ali A Bernevig B Andrei BA Neupert Titus T

Nature physics 20180901 9

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-boun ...[more]

PMID: 30349581

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Dataset Information

Higher-Order Topology in Bismuth.

Publications

Higher-Order Topology in Bismuth.

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