Non-universal role of local structure around the dynamic crossover
Résumé
The dynamics of glass-forming liquids is heterogeneous and displays growing spatial correlations upon cooling. Whether such behavior arises from heterogeneities in the local structure or more complex forms of amorphous order is a highly debated question. To clarify this issue, we study several model liquids within a coherent simulation framework based on the iso-configurational ensemble. We find that the correlation between the preferred local structure and the propensity of motion is pronounced in systems that deviate markedly from the mean-field picture of glassy dynamics and weak in models that adhere to it to a good extent. We conclude that the degree to which structural correlations affect the dynamics around the dynamic crossover is, in general, system-dependent.