Structural evolution of the silicon nanowire via molecular dynamics simulations: the double-strand atomic chain and the monatomic chain

We conducted molecular dynamics simulations to investigate the dynamic structural evolution of the silicon nanowire under the axial tension load. The formations of the double-strand atomic chain and the monatomic chain were observed before the silicon nanowire is completely broken. During these two stages, the zigzag and linear configurations appear alternately. Every sudden decrease in the calculated force curve corresponds to a transition from the linear chain to the zigzag chain, which indicates the force relaxation due to the insert of the new atom into the chain. The present work reveals the structural evolution on the atomic scale and discusses the formation mechanism of the double-strand atomic chain and the monatomic chain. Our findings provide insight into the understanding of the dynamic structural evolution of the low-dimensional silicon materials, which has potential applications in the design and fabrication of the silicon-based nanodevices.