Application of accelerated molecular dynamics schemes to the production of amorphous silicon

The evolving nature of a Stillinger-Weber modeled silicon glass is studied using two accelerated molecular dynamics scheme, specifically, hyperdynamics and self-guided algorithms due to Voter and due to Wu and Wang, respectively. We obtain an acceleration of the dynamics, a "boost," on the order of 20 without incurring any significant computational overhead. The validity of the results using accelerated methods is provided by comparison to a conventional molecular dynamics (MD) algorithm simulated under constant temperature conditions for more than 100 ns. We found that performing a sensitivity analysis of the effect of the parameters lambda and t1 before applying the self-guided MD scheme was important. Values of lambda greater than 0.1 and t1 equal to 1 ps were found to give improved structural evolution as compared to a conventional MD scheme. The hyperdynamics approximation scheme was found to be effective in obtaining boosts in the range of 4-12 for a small system without changing the dynamics of the evolution. However, for a large system size such an approach introduces significant perturbations to the pertinent equations of motion.