Anomalous Temperature Dependence of Heat Capacity During a Cooling-Heating Cycle in Glassy Systems

TL;DR

This paper explains the unusual temperature dependence of heat capacity in glassy systems during cooling and heating cycles using a model based on landscape paradigm and relaxation processes.

Contribution

It introduces a general model that accounts for anomalous heat capacity behavior in glassy systems, linking relaxation dynamics to observed phenomena.

Findings

Heat capacity anomalies are explained by a relaxation-based model.

Delayed energy relaxation causes sharp heat capacity rise during heating.

Model aligns well with experimental observations.

Abstract

Anomalous temperature dependence of heat capacity of glassy systems during a cooling-heating cycle has remained an ill-understood problem for a long time. Most of the features observed in the experimental measurement of the heat capacity of a supercooled liquid are shown here to be adequately explained by a general model. The model that we propose is motivated by the success of landscape paradigm, and describes \beta relaxation in terms of a collection of two-level systems and conceives \alpha relaxation as a \beta relaxation mediated cooperative transition in a double-well. The anomalous sharp rise in the heat capacity observed during heating is shown to have a kinetic origin, being caused by delayed energy relaxation due to nonequilibrium effects.