镍和铜纳米线阵列的超声子带隙

Band Gaps of Hypersonic Crystals Realized from Ni and Cu Nanowire Arrays

以实验可制备的镍、铜纳米线三角有序阵列为模型,用平面波法计算了它们的声子能带,发现了GHz频率的超声子带隙。在XΓ方向镍比铜更容易获得z模态带隙,而在ΓM方向上铜材料更容易激发xy模态的带隙以及在高频区获得更宽的带隙;通过调节填充率,可获得z模态和xy模态共同占据的带隙,正方晶格结构比三角晶格结构更有利于同时获得这两种模态的带隙。

The acoustic band gap structures of Ni and Cu nanowire triangular arrays （NWAs） were investigated by the plane wave expansion method. The structures were proposed on the basis of metallic NWAs realized from the state-of-the-art nanotechnology. The band gaps with GHz frequency can be achieved. We find that, in XF direction, Ni arrays are more easily to obtain the wider z mode band gaps. In FM direction, Cu arrays are more easily to motivate xy mode band gaps and larger band gaps at high frequency area. In some filling fraction, the band gap frequencies with z mode and xy mode can be obtained. Structurally, the two dimensional square lattice NWAs are more advantageous to produce hypersonic band gaps