Topological properties of two-dimensional photonic square lattice without \(C_4\) and \(M_{x(y)}\) symmetries

Rich topological phenomena, edge states and two types of corner states, are unveiled in a two-dimensional square-lattice dielectric photonic crystal without both \(C_4\) and \(M_{x(y)}\) symmetries. Specifically, non-trivial type-I corner states, which do not exist in systems with \(C_4\) and \(M_{x...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2022-03
Main Authors: Xiong, Langlang, Liu, Yufu, Zhang, Yu, Zheng, Yaoxian, Jiang, Xunya
Format: Article
Language:English
Subjects:
Crystal lattices
Photonic crystals
Quadrupoles
Topology
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Rich topological phenomena, edge states and two types of corner states, are unveiled in a two-dimensional square-lattice dielectric photonic crystal without both \(C_4\) and \(M_{x(y)}\) symmetries. Specifically, non-trivial type-I corner states, which do not exist in systems with \(C_4\) and \(M_{x(y)}\) since the degeneracy, are protected by non-zero quadrupole moment, no longer quantized to but less than \(0.5\). Excellent properties, e.g. sub-wavelength localization and air-concentrated field distribution, are presented. Type-II corner states, induced by long-range interactions, are easier realized due to asymmetry. This work broadens the topological physics for the symmetries-broken systems and provides potential applications.
ISSN:2331-8422
DOI:10.48550/arxiv.2203.09883