硅熔化特性的分子动力学模拟——不同势函数的对比研究

A comparative study of different potentials for molecular dynamics simulations of melting process of silicon

分别采用Stillinger-Weber(SW)势、修正的成熟原子嵌入模型(MEAM)势、Tersoff势和HOEP(highly optimized empirical potential)势来描述硅原子间相互作用,运用分子动力学方法对比模拟研究了四种势函数的硅晶体的体熔化和表面熔化特性.结果表明:四种势函数均能反映出硅的热膨胀、高温熔化和熔化时吸热收缩等基本物理规律.但综合对比发现,Tersoff势和MEAM势相对更适合描述硅的熔化和凝固过程,SW势次之,HOEP势则不适合描述硅的熔化和凝固过程.

Molecular dynamic simulations of bulk melting and surface melting of Si are carried out. The atomic interactions in Si are calculated by stillinger-weber （SW）, modified embedded-atom method （MEAM）, Tersoff and highly optimized empirical potential （HOEP） potentials respectively. The results show that the four potentials could exhibit the fundamental laws of Si, such as thermal expansion, melting at high temperature, endothermic and volume shrinkage in melting process. However, the detailed analyses demonstrate that the Tersoff and MEAM potentials are best to describe the melting and crystal growth of Si, SW potential is the next. The HOEP potential is even unsuitable for describing the melting and crystal growth of Si.