Symmetry-driven Phononic Metamaterials

TL;DR

This paper reviews recent advances in designing phononic crystals and metamaterials using symmetry principles to control acoustic and elastic wave propagation for various technological applications.

Contribution

It provides a comprehensive survey of how symmetry engineering in artificial media enables precise control of phononic responses and wave transport phenomena.

Findings

Symmetry principles enable tailored phononic responses in metamaterials.

Broken spatial and time symmetries can induce non-reciprocal phenomena.

Combining multiple symmetries leads to exotic phononic wave transport.

Abstract

Phonons are quasiparticles associated with mechanical vibrations in materials. They are at the root of the propagation of sound and elastic waves, as well as of thermal phenomena, which are pervasive in our everyday life and in many technologies. The fundamental understanding and control of phonon responses in natural and artificial media are key in the context of communications, isolation, energy harvesting and control, sensing and imaging. It has recently been realized that controlling different symmetry classes at the microscopic and mesoscopic scales in synthetic media offers a powerful tool to precisely tailor phononic responses for advanced acoustic and elastodynamic wave control. In this Review, we survey the recent progress in the design and synthesis of artificial phononic media, namely phononic crystals and metamaterials, guided by symmetry principles. Starting from tailored broken spatial symmetries, we discuss their interplay with time symmetries for non-reciprocal and non-conservative phenomena. We also address broader concepts that combine multiple symmetry classes to induce exotic phononic wave transport. We conclude with an outlook on future research directions based on symmetry engineering for the advanced control of phononic waves.