Shedding light on the self-assembly of stable SiC based cage nanostructures: A comprehensive molecular dynamics study

Abstract

A comprehensive molecular dynamics study to shed light on the existence of SiC based cage nanostructures SimCn, together with their stability, structural and other properties, in the range of compositions with n/(n+m) from 0.4 to 0.6 has been carried out using an efficient semi-empirical Hamiltonian scheme. Through this study, a series of self-assembled stable (even up to 2000K) SiC based SimCn cage structures are predicted. The mechanism of the stability and structural properties of the stable SimCn caged structures are analyzed in terms of their composition, bonding nature, surface environment, local strain, and types of ring structures. It is found that, for a given composition, the existence of the Si–C bonds, the sp2 bonding nature between the Si and C atoms, and the role played by the environmental mediation are crucial in forming the self-assembled and stable SiC cage structures. In particular, a “mending” process dictated by an environment-driven self-assembly is provided to show the possible transition from one stable cage structure to another cage structure of similar composition which might occur in the synthesis. The oscillatory behavior of the HOMO–LUMO gap as a function of the diameter of SimCn cages is also observed as expected. This work provides a possible path way for fabricating SiC based nano-cage structures.