Robustness of topological corner modes in photonic crystals

Barry Bradlyn,María Blanco De Paz,Dario Bercioux,Maia G Vergniory,Aitzol García-Etxarri,Paloma Arroyo Huidobro,Matthew Proctor

doi:10.1103/physrevresearch.2.042038

Abstract

We analyze the robustness of corner modes in topological photonic crystals, taking a $C_6$-symmetric breathing honeycomb photonic crystal as an example. First, we employ topological quantum chemistry and Wilson loop calculations to demonstrate that the topological properties of the bulk crystal stem from an obstructed atomic limit phase. We then characterize the topological corner modes emerging within the gapped edge modes employing a semi-analytical model, determining the appropriate real space topological invariants. For the first time, we provide a detailed account of the effect of long-range interactions on the topological modes in photonic crystals, and we quantify their robustness to perturbations. We conclude that, while photonic long-range interactions inevitably break chiral symmetry, the corner modes are protected by lattice symmetries.

Highlights

Robustness of topological corner modes in photonic crystalsMatthew Proctor ,1 Paloma Arroyo Huidobro ,2,* Barry Bradlyn ,3,† María Blanco de Paz ,4 Maia G
Photonic topological insulators host protected boundary modes that are robust against a range of defects and imperfections [1]
We have studied the emergence of topologically protected corner modes in breathing honeycomb photonic crystals (PhCs) particles

Summary

Robustness of topological corner modes in photonic crystals

Matthew Proctor ,1 Paloma Arroyo Huidobro ,2,* Barry Bradlyn ,3,† María Blanco de Paz ,4 Maia G. We analyze the robustness of corner modes in topological photonic crystals, taking a C6-symmetric breathing honeycomb photonic crystal as an example. We employ topological quantum chemistry and Wilson loop calculations to demonstrate that the topological properties of the bulk crystal stem from an obstructed atomic limit phase. We characterize the topological corner modes emerging within the gapped edge modes employing a semianalytical model, determining the appropriate real-space topological invariants. We provide a detailed account of the effect of long-range interactions on the topological modes in photonic crystals, and we quantify their robustness to perturbations. While photonic long-range interactions inevitably break chiral symmetry, the system is reducible to a chirally symmetric limit and the corner modes are protected by this together with lattice symmetries

Introduction

Published by the American Physical Society

Findings

Conclusions