Full band gap for surface acoustic waves in a piezoelectric phononic crystal

Abstract

A plane-wave-expansion method suited to the analysis of surface-acoustic-wave propagation in two-dimensional piezoelectric phononic crystals is described. The surface modes of a square-lattice Y-cut lithium niobate phononic crystal with circular void inclusions with a filling fraction of 63% are identified. It is found that a large full band gap with a fractional bandwidth of 34% exists for surface acoustic waves of any polarization and incidence, coincidentally with the full band gap for bulk waves propagating in the plane of the surface. The excitation of surface acoustic waves by interdigital transducers is discussed.

Scattering of surface acoustic waves by a phononic crystal revealed by heterodyne interferometry

“…Recently, elastic stop bands for surface acoustic waves ͑SAWs͒ have been at the center of a growing research effort. [3][4][5][6][7] Experimental demonstrations of directional 8 as well as full band gaps 9 in piezoelectric crystals at the micrometer scale have been reported. These studies have taken advantage of the possibility to directly generate and receive SAWs by using interdigital transducers ͑IDTs͒, 10 thus allowing testing of PCs in realistic device configurations via electrical measurements.…”

Simulations of acoustic waves bandgaps in a surface of silicon with a periodic hole structure in a thin nickel film

“…Literature gives information on investigation of bulk waves 5 and surface waves 6 in the media containing cylinders in a periodic lattices of different symmetries. Full energy gaps have been obtained thanks to a high acoustic contrast between the materials, 7 rotation of the elasticity tensors of the cylinders, 5,6 taking into account piezoelectric properties [8][9][10] or by making use of local resonance effect. 1,[12][13][14] The most often used simulation a Electronic mail: graczyk@amu.edu.pl methods are that of finite elements, that of finite differences 2,15 and that of plane waves.…”

Tuning of a hypersonic surface phononic band gap using a nanoscale two-dimensional lattice of pillars

“…Such composite structures comprise photonic crystals made of components of different permittivity, [1][2][3][4] magnonic crystals that are ferromagnetics of different permeability, 5,6 and phononic crystals. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] In phononic crystals of a heterogeneous one-dimensional (1D), 2D, or 3D structure, the elastic (acoustic) waves propagating in the medium are not simple plane waves that can be classified as transverse and longitudinal (or quasitransverse and quasilongitudinal). With a proper choice of material parameters and modulation spacing, it is possible to induce a complete band gap for which propagation of acoustic waves of arbitrary polarization and wave vector is forbidden.…”

“…Contrary to the linear dispersion relation in the long-wavelength limit, a mechanical wave of a wavelength comparable to the spacing may undergo multiple scattering at the interfaces of different elastic media, which leads to destructive interference and to the appearance of bands of forbidden frequencies at which propagation of mechanical waves is not allowed. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] A huge part of the advanced technological solutions in electronic devices is implemented on silicon substrates. A two-dimensional periodic nanostructure in the form of pillars deposited on such a substrate, or holes (inclusions) made in the substrate, enables the control of heat flow 13 and propagation of hypersonic surface acoustic waves (SAWs).…”