三维声子晶体带结构研究

运用平面波展开法计算由长方体散射物以面心立方结构排列于基体中形成的三维声子晶体的带结构,研究不同组分材料、散射物的填充率和长方体散射物的高与长之比 R_(HL)对带隙的影响.结果表明,将质量密度和波速大的散射体放在质量密度和波速小的基体中所形成的三维(面心立方)固态声子晶体有利于带隙的产生；散射体的填充率为中间值时带隙最宽；散射体的对称性强烈影响带隙,当 R_(HL)大于等于1时,带隙宽度随 R_(HL)的增加而减小,相反,当 R_(HL)小于1时,带隙宽度随 R_(HL)的增加而增加.

Band Structure of Three-dimensional Phononic Crystals

By using the plane-wave-expansion method,the band structure of three-dimension phononic crystals was calculated,in which the cuboid scatterers were arranged in a host with a face-centered-cubic (FCC) structure. The influences of a few factors such as the component materials,the filling fraction of scatterers and the ratio (R_(HL)) of the scatterer's height to its length on the band-gaps of phononic crystals were investigated. It is found that in the three-dimension solid phononic crystals with FCC structure,the optimum case to obtain band-gaps is to embed high-velocity and high-density scatterers in a low-velocity and low-density host.The maximum value of band-gap can be obtained when the filling fraction is in the middle value.It is also found that the symmetry of the scatterers strongly influences the band-gaps.For R_(HL)(?)1,the width of the band-gap decreases as R_(HL) increases.On the contrary,the width of the band-gap increases with the increase of R_(HL) when R_(HL) is smaller than 1.