Configuration space connectivity across the fragile-to-strong transition in silica.

We present a numerical analysis for SiO (2) of the fraction of diffusive direction f(diff) for temperatures T on both sides of the fragile-to-strong crossover. The T dependence of f(diff) clearly reveals this change in dynamical behavior. We find that for T above the crossover (fragile region) the system is always close to ridges of the potential energy surface (PES), while below the crossover (strong region), the system mostly explores the PES local minima. Despite this difference, the power law dependence of f(diff) on the diffusion constant, as well as the power law dependence of f(diff) on the configurational entropy, shows no change at the fragile-to-strong crossover.