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Helical topological edge states in a quadrupole phase

Liu, Feng, Deng, Hai-Yao ORCID: and Wakabayashi, Katsunori 2019. Helical topological edge states in a quadrupole phase. Physical Review Letters 122 (8) , 086804. 10.1103/PhysRevLett.122.086804

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A topological electric quadrupole is a recently proposed concept that extends the theory of electric polarization of crystals to higher orders. Such a quadrupole phase supports topological states localized on both edges and corners. In this work, we show that in a quadrupole phase of a honeycomb lattice, topological helical edge states and pseudospin-polarized corner states appear by making use of a pseudospin degree of freedom related to point group symmetry. Furthermore, we argue that a general condition for the emergence of helical edge states in a (pseudo)spinful quadrupole phase is the existence of either mirror or time-reversal symmetry. Our results offer a way of generating topological helical edge states without spin-orbital couplings.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: American Physical Society
ISSN: 0031-9007
Date of First Compliant Deposit: 20 January 2020
Last Modified: 04 May 2023 04:08

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