Observation of dislocation-induced topological modes in a three-dimensional acoustic topological insulator

• Main Authors: Xue, Haoran, Jia, Ding, Ge, Yong, Guan, Yi-Jun, Wang, Qiang, Yuan, Shou-Qi, Sun, Hong-Xiang, Chong, Yidong, Zhang, Baile
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Physics; Topological Phases of Matter; Acoustics
• Online Access: https://hdl.handle.net/10356/154803
• Institution: Nanyang Technological University

The interplay between real-space topological lattice defects and the reciprocal-space topology of energy bands can give rise to novel phenomena, such as one-dimensional topological modes bound to screw dislocations in three-dimensional topological insulators. We obtain direct experimental observations of dislocation-induced helical modes in an acoustic analog of a weak three-dimensional topological insulator. The spatial distribution of the helical modes is found through spin-resolved field mapping, and verified numerically by tight-binding and finite-element calculations. These one-dimensional helical channels can serve as robust waveguides in three-dimensional media. Our experiment paves the way to studying novel physical modes and functionalities enabled by topological lattice defects in three-dimensional classical topological materials.