Crystallization study of model tetrahedral semiconductors

Abstract

The microscopic mechanisms leading to crystallization are not yet fully understood. This is due, in part, to the lack of atomistic as well as interatomic interaction models for a wide range of materials that can lead to crystallization on a computer-simulation timescale, i.e. <100 ns. While the nucleation in close-packed systems has been extensively studied, there are almost no numerical results for covalent tetrahedral semiconductors. We present here the simulation results of crystallization from the liquid and amorphous states of a 1000-atom model of silicon, described with a modified Stillinger-Weber potential. With this potential, it is possible to crystallize the model in as little as a few nanoseconds, which opens a door to detailed studies of the nucleation processes in covalent systems. Using topological analysis, we also present a first characterization of the structural fluctuations of the nucleation centres in this system and give a rough estimate for the critical size of these centres. (Some figures in this article are in colour only in the electronic version)