基于第一性原理计算的C、Si、Ge的原子间相互作用势及晶格动力学

Ab Initio Interatomic Potentials and Lattice Dynamics of C,Si and Ge

运用第一原理赝势技术 ,计算了金刚石结构晶体 C、Si、Ge的结合能曲线以及总能随晶格畸变的变化 .根据陈氏三维晶格反演得到了 C- C、Si- Si、Ge- Ge的原子间相互作用对势 ;根据弹性系数的计算结果 ,确定了原子间相互作用的 MSW(m odified Stillinger- Weber)三体势参数 ;晶格动力学的计算结果和实验结果能够较好地符合 .给出了一种基于第一性原理的计算、无参数调节地确定原子间相互作用势的技术路线 。

Based on the first principle pseudopotential technique,the cohesive energies as the functions of the lattice distortion for C,Si and Ge are calculated.With the Chen's lattice inversion theorem,the interatomic pair potential components Φ C C , Φ Si Si and Φ Ge Ge are acquired;then the modified Stillinger Weber three body potential components are determined by the ab initio calculations of elastic constants.The calculations of the lattice dynamics for C,Si and Ge are in well agreement with the experiments according to the calculated interatomic potentials.A new approach to obtain the interatomic potentials is proposed,and the lattice dynamics for the materials with diamond structure is investigated based on ab initio calculations without disposable parameters.