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

Abstract

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.

6 pages, 4 figures

References in corpus (19)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Observation of phononic helical edge states in a mechanical 'topological insulator'
• Reflection symmetric second-order topological insulators and superconductors
• Efficient Light Funneling based on the non-Hermitian Skin Effect
• Topological Defects and Gapless Modes in Insulators and Superconductors
• Selective enhancement of topologically induced interface states in a dielectric resonator chain
• Topology of crystalline insulators and superconductors
• Helical Metal Inside a Topological Band Insulator
• Experimental discovery of bulk-disclination correspondence
• Acoustic realization of quadrupole topological insulators
• Realization of an acoustic third-order topological insulator
• Non-Hermitian route to higher-order topology in an acoustic crystal
• Gain and loss induced topological insulating phase in a non Hermitian electrical circuit
• Observation of Protected Photonic Edge States Induced By Real-Space Topological Lattice Defects
• Geometric Response and Disclination-Induced Skin Effects in Non-Hermitian Systems
• Vortex states in an acoustic Weyl crystal with a topological lattice defect
• Dislocation Non-Hermitian Skin Effect
• Bound States of Conical Singularities in Graphene-Based Topological Insulators