Enhancement of structural rearrangement in glassy systems under shear flow

TL;DR

This paper extends a mean field schematic model to analyze how shear flow influences the structural rearrangement and relaxation times in glassy systems, revealing different regimes depending on shear rate.

Contribution

It introduces a modified schematic model for glassy liquids under shear, highlighting the impact of shear rate on relaxation dynamics and structural rearrangements.

Findings

For weak shear, relaxation time is similar to the no-shear case.

For strong shear, relaxation time decreases inversely with shear rate.

Shear flow enhances local rearrangements in dense regions.

Abstract

We extend the analysis of the mean field schematic model recently introduced for the description of glass forming liquids to the case of a supercooled fluid subjected to a shear flow of rate $\gamma$. After quenching the system to a low temperature $T$, a slow glassy regime is observed before stationarity is achieved at the characteristic time $\tau_g$. $\tau_g$ is of the order of the usual equilibration time without shear $\tau_g^o$ for weak shear, $\gamma \tau_g ^o<1$. For larger shear, $\gamma \tau_g ^o>1$, local rearrangement of dense regions is instead enhanced by the flow, and $\tau_g \simeq 1/(T\gamma)$.