Using coupling slabs to tailor surface-acoustic-wave band structures in phononic crystals consisting of pillars attached to elastic substrates

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• 作者：Heng Zhang ; SiYuan Yu ; FuKang Liu ; Zhen Wang…
• 关键词：surface acoustic waves (SAWs) ; phononic crystals (PnCs) ; tailored band structure
• 刊名：Science China Physics, Mechanics & Astronomy
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：60
• 期：4
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics, general; Classical and Continuum Physics; Astronomy, Observations and Techniques;
• 出版者：Science China Press
• ISSN：1869-1927
• 卷排序：60

文摘

The propagation of surface acoustic waves (SAWs) in two-dimensional phononic crystals (PnCs) with and without coupling-enhancement slabs was theoretically investigated using a three-dimensional finite element method. Different piezoelectric substrates, for example, lithium niobate (LiNbO₃), gallium nitride (GaN), and aluminium nitride (AlN), were taken into account. Compared to the PnCs without coupling-enhancement slabs, the coupling between each pillar and its nearest neighbor was largely enhanced in the presence of slabs. The bandwidth of the first directional band gap increased markedly compared with its initial value for the PnCs without a slab (within square symmetry). In addition, with increasing thicknesses of the slabs bonded between neighboring pillars, the first directional band-gap and second directional band gap of the PnCs tend to merge. Therefore, the structure with coupling-enhancement slabs can be used as an excellent electrical band elimination filter for most electro-SAW devices, offering a new strategy to realize chip-scale applications in electroacoustic signal processing, optoacoustic modulation, and even SAW microfluidic devices.