碳化硅纳米线拉伸断裂及断裂表面接触的分子动力学模拟

Molecular Dynamics Simulation of Tensile Fracture and Fracture Surface Contact for SiC Nanowires

一维纳米材料的自愈合对于工业应用有着重要的意义,而晶体SiC纳米线则是一种拥有优异性能一维纳米材料.基于分子动力学方法,采用Tersoff势函数,对半径25(A),长150(A)的晶体SiC纳米线进行拉伸模拟,提取单个Si原子的位置和势能变化,发现原子断键后会形成悬键,并观察到了重新键合的现象;之后使纳米线完成了断裂表面的接触,发现了C-Si和Si-Si原子对间重新键合的现象,得到了自愈合后的纳米线.通过对单原子的势能变化进行分析,发现重新键合后的原子势能会降低,而系统为了达到稳定状态,会将悬键的势能驱动到最低,重新键合则是达到该状态的最有效路径,SiC纳米线也因此完成了自愈合.

The self-healing of one-dimensional nanomaterial is of great significance for industrial applications,and crystalline SiC nanowires are one-dimensional nanomaterials with excellent properties.In this paper,based on the molecular dynamics simulation and the Tersoff potential function,the crystalline SiC nanowires with a radius of 25 A and a length of 150 A are stretched,and the images of a single Si atom and the change of potential energies are extracted.It is found that atoms broke the bond,formed the dangling bond and the phenomenon of rebonding is observed;then the nanowires complete the contact between the broken surface,the phenomenon of rebonding between C-Si and Si-Si atom pairs is found,and the selfhealing nanowires are obtained.By analyzing the change of potential energy of single atom,it is found that the potential energy of atoms after rebonding will be reduced.In order to achieve the stable state,the potential energy of the danling bond will be driven to the lowest,and rebonding is the most effective path to this state,so self-healing of SiC nanowires is completed.