Aging effects manifested in the potential energy landscape of a model glass former

TL;DR

This study uses molecular dynamics simulations to explore how aging affects the potential energy landscape of a model glass, revealing transient behaviors and comparing results with a trap model.

Contribution

It introduces a detailed analysis of aging effects on the energy landscape of a glass-forming liquid, including the novel observation of a transient two-peak structure after temperature up-jumps.

Findings

Transient two-peak structure in metabasins after up-jump

Qualitative agreement with a Gaussian trap model for small systems

Major averaging effects limit detailed comparison for larger systems

Abstract

We present molecular dynamics simulations of a model glass-forming liquid (the binary Kob-Anderson Lennard-Jones model) and consider the distributions of inherent energies and metabasins during aging. In addition to the typical protocol of performing a temperature jump from a high temperature to a low destination temperature, we consider the temporal evolution of the distributions after an 'up-jump', i.e. from a low to a high temperature. In this case the distribution of megabasin energies exhibits a transient two-peak structure. Our results can qualitatively be rationalized in terms of a trap model with a Gaussian distribution of trap energies. The analysis is performed for different system sizes. A detailed comparison with the trap model is possible only for a small system because of major averging effects for larger systems.