Nucleation and crystallization process of silicon using Stillinger-Weber potential

TL;DR

This study investigates the nucleation and crystallization of silicon modeled with Stillinger-Weber potential, revealing a first-order liquid-to-crystal transition, critical cluster size, and insights into nucleation theory discrepancies.

Contribution

It provides detailed simulation evidence of silicon nucleation, highlighting differences from classical nucleation theory and suggesting the influence of a low-density liquid phase.

Findings

Critical cluster size is about 175 atoms at 0.75 T_m.

Cluster lifetime distribution follows an inverse Gaussian distribution.

Free energy curve from simulations differs from classical theory predictions.

Abstract

We study the homogeneous nucleation process in Stillinger-Weber silicon in the NVT ensemble. A clear first-order transition from the liquid to crystal phase is observed thermodynamically with kinetic and structural evidence of the transformation. At 0.75 T_m, the critical cluster size is about 175 atoms. The lifetime distribution of clusters as a function of the maximum size their 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 in the nucleation process.