Higher-Order Topology in Bismuth.
- Schindler F Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
- Wang Z Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
- Vergniory MG Donostia International Physics Center, P. Manuel de Lardizabal 4, 20018 Donostia-San Sebastian, Spain.
- Cook AM Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
- Murani A LPS, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France.
- Sengupta S CSNSM, Univ. Paris-Sud, IN2P3, UMR 8609, F-91405 Orsay Cedex, France.
- Kasumov AY LPS, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France.
- Deblock R LPS, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France.
- Jeon S Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
- Drozdov I Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
- Bouchiat H LPS, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France.
- Guéron S LPS, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France.
- Yazdani A Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
- Bernevig BA Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
- Neupert T Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
- 2018-10-24
Published in:
- Nature physics. - 2018
English
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.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1038/s41567-018-0224-7
- PMID 30349581
- Persistent URL
- https://sonar.ch/global/documents/95322
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