Realization of an Acoustic Third-Order Topological Insulator

The recent discovery of higher-order topological insulators (TIs) has opened new possibilities in the search for novel topological materials and metamaterials. Second-order TIs have been implemented in two-dimensional (2D) systems exhibiting topological "corner states," as well as three-di...

Full description

Saved in:
Bibliographic Details
Published in:Physical review letters 2019-06, Vol.122 (24), p.244301-244301, Article 244301
Main Authors: Xue, Haoran, Yang, Yahui, Liu, Guigeng, Gao, Fei, Chong, Yidong, Zhang, Baile
Format: Article
Language:English
Subjects:
Acoustic insulation
Acoustic measurement
Acoustics
Diamonds
Metamaterials
Topological insulators
Topology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The recent discovery of higher-order topological insulators (TIs) has opened new possibilities in the search for novel topological materials and metamaterials. Second-order TIs have been implemented in two-dimensional (2D) systems exhibiting topological "corner states," as well as three-dimensional (3D) systems having one-dimensional (1D) topological "hinge states." Third-order TIs, which have topological states three dimensions lower than the bulk (which must thus be 3D or higher), have not yet been reported. Here, we describe the realization of a third-order TI in an anisotropic diamond-lattice acoustic metamaterial. The bulk acoustic band structure has nontrivial topology characterized by quantized Wannier centers. By direct acoustic measurement, we observe corner states at two corners of a rhombohedronlike structure, as predicted by the quantized Wannier centers. This work extends topological corner states from 2D to 3D, and may find applications in novel acoustic devices.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.122.244301