Helical Topological Edge States in a Quadrupole Phase
Mesoscale and Nanoscale Physics
2019-03-06 v2
Abstract
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 honeycomb lattice, topological helical edge states and pseudo-spin-polarized corner states appear by making use of a pseudo-spin degree of freedom related to point group symmetry. Furthermore, we argue that a general condition for emergence of helical edge states in a (pseudo-)spinful quadrupole phase is mirror or time-reversal symmetry. Our results offers a way of generating topological helical edge states without spin-orbital couplings.
Cite
@article{arxiv.1809.10824,
title = {Helical Topological Edge States in a Quadrupole Phase},
author = {Feng Liu and Hai-Yao Deng and Katsunori Wakabayashi},
journal= {arXiv preprint arXiv:1809.10824},
year = {2019}
}