Nucleation and crystallization process of silicon using the Stillinger-Weber potential

We study the homogeneous nucleation process in Stillinger-Weber silicon in the canonical ensemble. A clear first-order transition from the liquid to crystal phase is observed thermodynamically with kinetic and structural evidence of the transformation. At 0.75Tₘ, the critical cluster size is about 175 atoms. The lifetime distribution of clusters as a function of the maximum size they reach follows an inverse Gaussian distribution as was predicted recently from the classical theory of nucleation (CNT). However, while there is a qualitative agreement with the CNT, the free-energy curve obtained from the simulations differs significantly from the theoretical predictions, suggesting that the low-density liquid phase found recently could play a role at the interface between the crystallite and the surrounding liquid during the nucleation process.