Miniaturization of Floquet topological insulators for airborne acoustics by thermal control

Abstract

The development of topological insulators in condensed matter systems that break time-reversal symmetry using magnetic bias has inspired a quest for similar effects in classical acoustic waves. The acoustic topological insulator is a revolutionary design to control acoustics in isolation and broadband unidirectional transmission, which is topologically robust and immune to structural disorders or defects. Currently, these fascinating properties have been investigated through fan-induced moving media, acoustic capacitance adjustment, and acoustic metamaterials. However, most of them are still associated with disadvantages including extra noise, bulky volume, and limited dynamic controlling performance. In this study, we propose an approach which could possibly overcome these limitations by introducing a modulation scheme of the temperature difference in a lattice of resonators, which demonstrates that the Floquet topological insulators with thermal control can realize topologically robust and nonreciprocal acoustic propagation. This controlling strategy provides an alternative platform to conduct acoustic topological applications, especially for noiseless and miniaturized airborne acoustics. The use of thermal modulation could potentially provide a platform for miniaturizing topologically insulating devices for airborne acoustics.