Stable film creation by swept swapping in simulations

Random atom-pair swapping has been used in molecular dynamics simulations to accelerate the densification and stabilization of glass structures. Equilibrating them deeply below the glass transition requires very long simulations during which crystallization is a constant danger. Here we efficiently create films of size-dispersed, Lennard-Jones atoms which are stabilized down to 0.75 of the glass transition temperature (Tg), have density increased up to 3% and stability up to 500 times the as-deposited film. We achieve this using Metropolis rule Monte Carlo swap in a limited region that moves up through the film. This approach creates a large-atom-rich wave at the top of the swap region; the dis-/re-proportionation processes involved in creating this wave are possibly the source of our densification efficiency. Densification slows down at the highest densities below 0.75 Tg; we will discuss the change in dynamics occurring at this point.