中文摘要：

采用SCC-DFTB方法,研究了不同手性参数的单臂硅纳米管在不同拉伸应变作用下的稳定性和带隙变化。结果表明,随着拉伸应力的增加,不同孔径的硅纳米管的形成能都增大,稳定性降低。当拉伸应变大于6%时,表现出较明显的尺寸效应,大孔径的硅纳米管相对不容易被拉伸。当拉伸应变小于4%时,不同孔径的硅纳米管的带隙总体都会增大,然后随着拉伸应变的增加,带隙逐渐变小,当拉伸应变大于9%之后,则变成了金属。拟合得到了不同孔径和应变下硅纳米管的带隙变化分布图,为实验上制备不同的应变和不同的孔径纳米管,进行带隙调控提供一定的理论参考。

英文摘要：

The stability and band gap of armchair silicon nanotubes under different tensile strain with different chiral parameters are studied by method of SCC-DFTB in this paper.The calculated results show that the formation energy of the silicon nanotubes with different aperture is increased,which means that the stability is reduced with the increase of tensile stress.A significant size effect appears when the tensile strain is more than 6%,and large diameter silicon nanotubes are relatively difficult to be stretched.When tensile strain is less than 4%,the band gap of silicon nanotubes with different aperture will increase entirely,and then band gap becomes more narrow with the increase of tensile strain,and finally silicon nanotubes turn into metallic after tensile strain reaches more than 9%.A phase diagram of silicon nanotubes under different sizes and strains is obtained,which can be referred to the band gap control on preparation of silicon nanotubes with different strain and different aperture in the experiments.