Non-monotonic pressure dependence of the dynamics of soft glass-formers at high compressions

TL;DR

This study reveals a non-monotonic relationship between pressure and the dynamics of soft glass-formers, identifying a crossover pressure where structural and vibrational properties peak, influencing glass transition behavior.

Contribution

It uncovers the link between zero-temperature jammed states and high-pressure glass dynamics, highlighting structural and vibrational precursors to the glass transition.

Findings

Maxima of glass transition temperature, heterogeneity, and fragility at $P_d$

States at $P_d$ exhibit highest bond orientational order and fluctuations

Normal modes are least localized with highest energy barriers near $P_d$

Abstract

In molecular dynamics simulations of soft glass-formers interacting via repulsions, we find that the glass transition temperature, dynamical heterogeneity, and glass fragility reach their maxima at the same crossover pressure $P_d$. Our analysis of the zero-temperature jammed states indicates that states at $P_d$ have the highest bond orientational order with the largest spatial fluctuation. Correspondingly, the low-frequency normal modes of vibration are the least localized and the average potential energy barrier along these modes are the highest for jammed states in the vicinity of $P_d$. The reentrant glass transition and dynamics of supercooled liquids are thus predictable by these structural and vibrational precursors in the zero-temperature jammed states.