Some Finite Size Effects in Simulations of Glass Dynamics

TL;DR

This study uses molecular dynamics simulations to explore finite size effects on silica glass dynamics, revealing significant impacts on relaxation times and mobility, with effects diminishing at higher densities transforming the glass into a fragile form.

Contribution

It demonstrates the presence and variability of finite size effects in glass simulations, highlighting their dependence on the glass's fragility and density.

Findings

Large finite size effects influence relaxation times in silica.

Finite size effects are weaker in fragile glass formers at high densities.

System size impacts the dynamics of glassy materials.

Abstract

We present the results of a molecular dynamics computer simulation in which we investigate the dynamics of silica. By considering different system sizes, we show that in simulations of the dynamics of this strong glass former surprisingly large finite size effects are present. In particular we demonstrate that the relaxation times of the incoherent intermediate scattering function and the time dependence of the mean squared displacement are affected by such finite size effects. By compressing the system to high densities, we transform it to a fragile glass former and find that for that system these types of finite size effects are much weaker.