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Reflection-Symmetric Second-Order Topological Insulators and Superconductors

Josias Langbehn, Yang Peng, Luka Trifunovic, Felix von Oppen, and Piet W. Brouwer
Phys. Rev. Lett. 119, 246401 – Published 11 December 2017
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Abstract

Second-order topological insulators are crystalline insulators with a gapped bulk and gapped crystalline boundaries, but with topologically protected gapless states at the intersection of two boundaries. Without further spatial symmetries, five of the ten Altland-Zirnbauer symmetry classes allow for the existence of such second-order topological insulators in two and three dimensions. We show that reflection symmetry can be employed to systematically generate examples of second-order topological insulators and superconductors, although the topologically protected states at corners (in two dimensions) or at crystal edges (in three dimensions) continue to exist if reflection symmetry is broken. A three-dimensional second-order topological insulator with broken time-reversal symmetry shows a Hall conductance quantized in units of e2/h.

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  • Received 12 August 2017

DOI:https://doi.org/10.1103/PhysRevLett.119.246401

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

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Topological Insulators Turn a Corner

Published 11 December 2017

Theorists have discovered topological insulators that are insulating in their interior and on their surfaces but have conducting channels at corners or along edges.

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Authors & Affiliations

Josias Langbehn, Yang Peng*, Luka Trifunovic, Felix von Oppen, and Piet W. Brouwer

  • Dahlem Center for Complex Quantum Systems and Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

  • *Corresponding author. yang.peng@fu-berlin.de

See Also

(d2)-Dimensional Edge States of Rotation Symmetry Protected Topological States

Zhida Song, Zhong Fang, and Chen Fang
Phys. Rev. Lett. 119, 246402 (2017)

Electric multipole moments, topological multipole moment pumping, and chiral hinge states in crystalline insulators

Wladimir A. Benalcazar, B. Andrei Bernevig, and Taylor L. Hughes
Phys. Rev. B 96, 245115 (2017)

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Vol. 119, Iss. 24 — 15 December 2017

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