论文标题
具有有效性的硅分子动力学模拟的双晶格潜力
Double lattice potential for molecular dynamics simulation of silicon with demonstrated validity
论文作者
论文摘要
为了重现硅的钻石结构，提出了分子动力学（MD）模拟的双晶格（DL）电势。对于MD模拟的有效性测试，Tersoff电势，Stillinger和Weber（SW）电位，依赖环境的原子体（EDI）电位，电荷优化了多体（COMB）电位以及改进的嵌入式原子（MEAM）电位。通过计算原子与最接近的邻居之间的原子和角度之间的角度之间的距离和角度之间的距离的分布函数来识别模拟硅系统的晶格。结果也与完美的硅晶体进行了比较。使用上述电势从MD模拟中计算出晶格，结晶温度和弹性常数。结果表明，具有改良的Tersoff，SW，EDI，COMB和MEAM电位的系统无法表现出钻石结构，并且只有DL电位才能提供钻石晶格。 DL电位的基态是Wurtzite结构，在快速冷却过程中形成的亚稳态是立方钻石结构。从具有DL电位的模拟获得的物理参数与实验结果一致。这项工作表明，只有DL势可以有效地模拟以上电位之间的硅晶体。
To reproduce the diamond structure of silicon, double lattice (DL) potential constructed from two interatomic potentials for face centered cubic (fcc) lattice, is proposed for molecular dynamics (MD) simulations. For the validity test of MD simulation, the Tersoff potential, the Stillinger and Weber (SW) potential, the environment-dependent interatomic (EDI) potential, the charge optimized many-body (COMB) potential, and the modified embedded-atom (MEAM) potential have been also employed for comparison. The crystal lattice of simulated silicon system is identified by calculating the distribution functions of the distances between the atoms and the angles between the lines linking an atom with its nearest neighbors. The results are also compared with the perfect silicon crystal. The crystal lattice, the crystallization temperature, and elastic constants have been calculated from MD simulations using above potentials. The results show that the systems with modified Tersoff, SW, EDI, COMB, and MEAM potentials could not exhibit the diamond structure and only the DL potential gives diamond lattice. The ground state for DL potential is the wurtzite structure, and the metastable state formed during rapid cooling is the cubic diamond structure. The physical parameters obtained from the simulation with DL potential are in agreement with the experiment results. This work indicated that only DL potential is valid for MD simulation of silicon crystal among above various potentials.
