中文摘要：

通过分子动力学方法模拟了在碳纳米管内填充一定数目的半导体元素硅形成碳纳米管-硅纳米线复合结构的过程,并采用Lindemann指数研究了这种复合结构的热稳定性.计算结果表明,当考虑碳纳米管和硅纳米线轴向方向的周期性边界条件之后,在C（13,0）和C（14,0）碳纳米管内能够形成亚稳结构的硅纳米线Si16NW和Si20NW,从而获得一种碳纳米管-硅纳米线的新型复合结构.通过计算这种复合结构的Lindemann指数,可以看到由于碳纳米管的保护作用,碳纳米管包裹的硅纳米线的熔点远高于自由空间中相同尺寸的硅纳米线熔点.而通过硅纳米线团簇和不同管径的碳纳米管相互作用能的计算,我们发现C（14,0）纳米管除了对Si20NW有一种限制性保护作用之外,对硅纳米线还存在一种径向应力（径向压缩）,这种应力使碳纳米管内的Si20NW具有更高的熔点,而当Si20NW轴向方向为自由边界条件时,这种径向应力将通过硅纳米线的形变而释放出来,从而使碳纳米管内的硅纳米线团簇的熔点降低更多.

英文摘要：

We have studied the formation process of carbon nanotube-silicon nanowire compound structures by using empirical molecular dynamics method and their thermal stability by empolying Lindemann index. Our results show that, in some cases, liquid Si encapsulated in C（13,0） and C（14,0） carbon nanotubes can crystallize into nanowires composed of linked Si_16 and Si_20 fullence cages, respectively. The Si nanowire inside the carbon nanotube has higher melting temperature then the Si nanowire in free space. By calculating interaction potential energy between SiNW clusters and carbon nanotubes with different diameters, we have found that the radial stress on Si_20NW induced by the carbon nanotube can increase melting temperature of Si_20NW. For Si_20NW under free boundary condition, this radial stress can be released by the deformation of Si_20NW which results in decrease of the melting temperature of Si_20NW cluster.