Activated dynamics and effective temperature in a steady state sheared glass

TL;DR

This study uses molecular dynamics simulations to explore how shear stress, inherent structure energy, and effective temperature behave in a sheared glass, revealing that the effective temperature governs the system's behavior in certain regimes.

Contribution

It introduces a detailed analysis of the effective temperature in sheared glasses and its relation to rheology and inherent structure energy across different regimes.

Findings

At high temperatures, $T_{eff}$ approaches the bath temperature as strain rate decreases.

Below the glass transition temperature, shear stress approaches a yield stress and $T_{eff}$ approaches a limiting value.

In shear-dominated regimes, shear stress and inherent structure energy collapse onto a single curve when plotted against $T_{eff}$.

Abstract

We conduct nonequilibrium molecular dynamics simulations to measure the shear stress, the average inherent structure energy, and the effective temperature $T_{eff}$ of a sheared model glass as a function of bath temperature $T$ and shear strain rate. For $T$ above the glass transition temperature $T_0$, the rheology approaches a Newtonian limit and $T_{eff}$ approaches $T$ as the strain rate approaches zero, while for $T<T_0$, the shear stress approaches a yield stress and $T_{eff}$ approaches a limiting value near $T_0$. In the shear-dominated regime at high $T$, high strain rate or at low $T$, we find that the shear stress and the average inherent structure energy each collapse onto a single curve as a function of $T_{eff}$. This indicates that $T_{eff}$ is controlling behavior in this regime.