Modeling Vibrational Behavior of Silicon Nanowires Using Accelerated Molecular Dynamics Simulations

Abstract

The classical methods utilized for modeling the nano-scale systems are not practical because of the enlarged surface effects that appear at small dimensions. Contrarily, implementing more accurate methods results in prolonged computations as these methods are highly dependent on quantum and atomistic models and they can be employed for very small sizes in brief time periods. In order to speed up the molecular dynamics (MD) simulations of the silicon structures, coarse-graining (CG) models are put forward in this research. The procedure consists of establishing a map between the main structure’s atoms and the beads comprising the CG model and modifying the systems parameters such that the original and the CG models reach identical physical parameters. The accuracy and speed of this model is investigated by carrying out various static and dynamic simulations and assessing the effect of size. The simulations show that for a nanowire with thickness over 10a, where parameter a is the lattice constant of diamond structure, the Young modulus obtained by CG and MD models differs less than 5 percent. The results also show that the corresponding CG model behaves 190 time faster compared to the AA model.