Abstract
We employ a recently introduced class of artificial structurally-disordered phononic structures that exhibit large and robust elastic frequency band gaps for efficient phonon guiding. Phononic crystals are periodic structures that prohibit the propagation of elastic waves through destructive interference and exhibit large band gaps and ballistic propagation of elastic waves in the permitted frequency ranges. In contrast, random-structured materials do not exhibit band gaps and favour localization or diffusive propagation. Here, we use structures with correlated disorder constructed from the so-called stealthy hyperuniform disordered point patterns, which can smoothly vary from completely random to periodic (full order) by adjusting a single parameter. Such amorphous-like structures exhibit large band gaps (comparable to the periodic ones), both ballistic-like and diffusive propagation of elastic waves, and a large number of localized modes near the band edges. The presence of large elastic band gaps allows the creation of waveguides in hyperuniform materials, and we analyse various waveguide architectures displaying nearly 100% transmission in the GHz regime. Such phononic-circuit architectures are expected to have a direct impact on integrated micro-electro-mechanical filters and modulators for wireless communications and acousto-optical sensing applications.
Highlights
Phononic crystals are artificial materials with periodically arranged components
Phononic band gap materials [2] have a direct impact on a vast number of applications, including audible filters [3], acoustic diodes [4], ultrasound imaging [5], optomechanics [6], heat conduction, and energy harvesting [7,8,9,10], etc
This mode contributes to the opening of the band gap, which in the case of a square periodic structure (PC) of lattice constant a = 1 μm has a relative size of 64%, extending from
Summary
Phononic crystals are artificial materials with periodically arranged components. They were introduced more than two decades ago as the elastic waves’ analogue of photonic crystals [1]. Disorder in elastic media [11,12,13,14] is important for a large range of applications including acoustic filters [15], piezoelectric materials [16], biological materials [17], fracture [18], and manipulation of the thermal conductance [7,19], etc Despite this and in contrast to the vast body of studies dealing with the effects of disorder on photonic structures, the research of disordered phononic systems and the effect of disorder on phononic band gaps has been sparse, with a few notable exceptions [12,20,21,22]. We theoretically analyse propagation of elastic waves in the GHz frequency region and extensively explore various architecture designs to discuss
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