Topological materials for full-vector elastic waves
arXiv:2201.04950 · doi:10.1093/nsr/nwac203
Abstract
Elastic wave manipulation is important in a wide variety of scales in applications including information processing in tiny elastic devices and noise control in big solid structures. The recent emergence of topological materials opens a new avenue toward modulating elastic waves in solids. However, because of the full-vector feature, and the complicated couplings of the longitudinal and transverse components of elastic waves, manipulating elastic waves is generally difficult, compared with manipulating acoustic waves (scalar waves) and electromagnetic waves (vectorial waves but transverse only). Up to date, topological materials, including insulators and semimetals, have been realized for acoustic and electromagnetic waves. Although topological materials of elastic waves have also been reported, the topological edge modes observed all lie on the domain wall. A natural question can be asked: whether there exists an elastic metamaterial with the topological edge modes on its own boundary only? Here, we report a 3D metal-printed bilayer metamaterial, insulating topologically the elastic waves. By introducing the chiral interlayer couplings, the spin-orbit couplings for elastic waves are induced, which give rise to nontrivial topological properties. The helical edge states with the vortex feature are demonstrated on the boundary of the single topological phase. We further show a heterostructure of the metamaterial, which exhibits tunable edge transport. Our work may have potential in devices based on elastic waves in solids.
References in corpus (26)
- Topological Insulators
- Topological insulators and superconductors
- Magic-angle graphene superlattices: a new platform for unconventional superconductivity
- Quantum Spin Hall Effect in Graphene
- Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
- Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
- Observation of a phononic quadrupole topological insulator
- An equivalent expression of Z2 Topological Invariant for band insulators using Non-Abelian Berry's connection
- Topologically protected elastic waves in phononic metamaterials
- The space group classification of topological band insulators
- Experimental discovery of bulk-disclination correspondence
- Observation of topological valley modes in an elastic hexagonal lattice
- Valley Topological Phases in Bilayer Sonic Crystals
- Experimental realization of on-chip topological nanoelectromechanical metamaterials
- Designing Perturbative Metamaterials from Discrete Models: From Veselago lenses to topological insulators
- Higher-order topological semimetal in acoustic crystals
- Observation of topologically protected helical edge modes in Kagome elastic plates
- Subwavelength and directional control of flexural waves in zone-folding induced topological plates
- Observation of a phononic higher-order Weyl semimetal
- Effective theory of quadratic degeneracies
- Universal probes of two-dimensional topological insulators: Dislocation and pi-flux
- Topological light-trapping on a dislocation
- Experimental characterization of fragile topology in an acoustic metamaterial
- Acoustic spin-Chern insulator induced by synthetic spin-orbit coupling with spin conservation breaking
- Dial-in Topological Metamaterials Based on Bistable Stewart Platform
- Dislocation as a bulk probe of higher-order topological insulators