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

作　　者：Heng Zhang SiYuan Yu FuKang Liu Zhen Wang MingHui Lu XiaoBo Hu YanFeng Chen XianGang Xu 

机构地区：[1]State Key Laboratory of Crystal Materials,Shandong University [2]National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering,Nanjing University

出　　处：《Science China(Physics,Mechanics & Astronomy)》2017年第4期45-50,共6页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Basic Research Program of China (GrantNos.2013CB632904,and 2013CB63 2702);the National Nature Science Foundation of China(Grant Nos.11134006,11625418,11474158,and 51472114);the Natural Science Foundation of Jiangsu Province(Grant No.BK20140019);the project funded by the Priority Academic Program Development of Jiangsu Higher Education

摘　　要：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(LiNbO_3),gallium nitride(GaN),and aluminium nitride(A1N),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.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 （A1N）, 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.

关 键 词：surface acoustic waves(SAWs) phononic crystals(PnCs) tailored band structure 

分 类 号：O735[理学—晶体学]