三组元声子晶体中的缺陷态

运用基于平面波的超元胞方法，研究作为缺陷引入的第三组元材料(四氯化碳、水)对二维二组元声子晶体(水/水银，四氯化碳/水银)带结构的影响.结果表明，二组元声子晶体在引入第三组元点缺陷/线缺陷后，在原来的带结构中会出现缺陷态/带，原带隙的位置、宽度变化不大；缺陷态/带频率主要受第三组元材料物性参数的影响；这些缺陷态都是局域化的.因此，在具有宽带隙的二组元体系中引入适当的第三组元点缺陷/线缺陷，让缺陷态/带频率落在二组元体系的带隙中，就可以形成特殊的滤声态/波导态.声子晶体的这一特性对于声波/弹性波的传播和新的声学应用具有重要意义. 关键词： 声子晶体 三组元 点缺陷 线缺陷

Defect states in three-component phononic crystal

Using the supercell plane wave method, we investigated the effect of the third component material as defects modifying band structure of two-dimension two-component phononic crystal (PC). It is shown that adding the third material as point defect/linear defects in the two-component PC, defect states/bands can appear in the original band gap whose position and width would have only minor changes. The frequency of the defect states/bands are affected by the third material's characteristics; and all the defect states are localized. Therefore, adding proper third material as point/linear defects to the two-component system with wide band gap where defect states/bands will fall in, some special filtered/guided states will be formed. This property has important significance in acoustic /elastic wave propagating and new acoustic applications.