The topological properties of an object, associated with an integer called the topological
invariant, are global features that cannot change continuously but only through abrupt …

Acoustic metamaterials can manipulate and control sound waves in ways that are not
possible in conventional materials. Metamaterials with zero, or even negative, refractive …

Architected materials that consist of multiple subelements arranged in particular orders can
demonstrate a much broader range of properties than their constituent materials. However …

The coupling of waves between the piezoelectric generators, detectors, and propagating
media is challenging due to mismatch in the acoustic properties. The mismatch leads to the …

Within a time span of 15 years, acoustic metamaterials have emerged from academic
curiosity to become an active field driven by scientific discoveries and diverse application …

Manipulating the properties of the isofrequency contours (IFCs) of materials provides a
powerful means of controlling the interaction between light and matter. Hyperbolic …

Polaritons are a hybrid class of quasiparticles originating from the strong and resonant
coupling between light and matter excitations. Recent years have witnessed a surge of …

The introduction of engineered resonance phenomena on surfaces has opened a new
frontier in surface science and technology. Pillared phononic crystals, metamaterials, and …

The causal nature of the acoustic response dictates an inequality that relates the two most
important aspects of sound absorption: the absorption spectrum and the sample thickness …

We report a new type of phononic crystals with topologically nontrivial band gaps for both
longitudinal and transverse polarizations, resulting in protected one-way elastic edge …