二维声子晶体同质位错结缺陷态特性

利用平面波展开法结合超原胞的方法研究了二维声子晶体同质位错结的缺陷态.分别研究了横向位错和纵向位错两种情况，研究结果表明：横向位错效应与线缺陷相似，它可以使处于禁带频率范围内的声波沿位错通道进行传播，形成声波导；纵向位错效应则类似于点缺陷，位错线两边三个最接近的散射子形成腔，因而能够产生局域模.另外，横向位错距离和纵向位错距离的大小将影响缺陷带的位置和数量，因此，可以通过调节横向位错距离或纵向位错距离来人为的控制同质位错结中的缺陷带. 关键词： 声子晶体 同质位错结 缺陷态

Defect states of homogeneity dislocation structures in two-dimensional phononic crystal

The defect states in two-dimensional phononic crystal homogeneity dislocation structures has been studied by means of the plane-wave expansion method in combination with a supercell technique. Transverse dislocation structures and longitudinal dislocation structures are investigated respectively. The results show that, acting as a line defect, transverse dislocation structures can mold the flow of sound in the bandgap along the dislocation channel and form the so called waveguides; while longitudinal dislocation structures, which act just as point defects, can form a cavitylike void surrounded by the three nearest cylinders around the dislocation line to create a localized state. In addition, the number and the position of defect bands strongly depend on the transverse and longitudinal dislocation displacement, so we can artificially control the defect bands by adjusting the transverse and longitudinal dislocations of lattices in a homogeneity islocation structures.