修正Tersoff势在熔态硅分子动力学模拟中的应用

APPLICATION OF THE MODIFIED TERSOFF POTENTIAL TO LIQUID SILICON BY MOLECULAR DYNAMICS SIMULATION

采用Ｔｅｒｓｏｆｆ 势，通过粒子间相互作用距离Ｒ、Ｓ的不同取值加以修正，并进行了液态硅的分子动力学模拟。模拟的结果表明其径向分布函数能与Ｘ 射线衍射、中子散射实验相一致。模拟得到液态硅配位数６－９ ，键长０－２５４ｎｍ 。键角几率分布出现两个峰值，～５７°和～１０２°，表明液态硅中存在复杂的结构。模拟结果还表明，液态硅中硅原子间联接成一种网络状结构，但大多数硅原子与其近邻硅原子仍保持近似于正四面体的局部结构。

A modified Tersoff potential developed by extending atomic interaction distance has been applied to simulate the properties of liquid silicon by molecular dynamics. The radial distribution functions with coordination number 6.9 and bond length 0.254nm obtained from the simulation are in good agreement with the experimental results from X-ray diffraction and neutron scattering. The presence of two peaks, ～57° and ～102°,in bond angle probability distribution indicates a very complicated structure in liquid silicon. The configurations simulated show that a chain-network structure is formed among silicon stoms in liquid silicon, and a majority of atoms remain tetrahedral local structure with near-neighbour atoms.