Density-temperature scaling of the fragility in a model glass-former

TL;DR

This paper investigates how density-temperature scaling influences the fragility of a model glass-former, revealing weak density dependence and consistency with the Adam-Gibbs relation, thus enhancing understanding of glass transition dynamics.

Contribution

It demonstrates the impact of density-temperature scaling on fragility and confirms the Adam-Gibbs relation exhibits similar scaling behavior in a model glass-former.

Findings

Weak density dependence of fragility observed

DT scaling applies to the Adam-Gibbs relation

Scaling exponent aligns with other measurement methods

Abstract

Dynamical quantities such as the diffusion coefficient and relaxation times for some glass-formers may depend on density and temperature through a specific combination, rather than independently, allowing the representation of data over ranges of density and temperature as a function of a single scaling variable. Such a scaling, referred to as density - temperature (DT) scaling, is exact for liquids with inverse power law (IPL) interactions but has also been found to be approximately valid in many non-IPL liquids. We have analyzed the consequences of DT scaling on the density dependence of the fragility in a model glass-former. We find the density dependence of kinetic fragility to be weak, and show that it can be understood in terms of DT scaling and deviations of DT scaling at low densities. We also show that the Adam-Gibbs relation exhibits DT scaling and the scaling exponent computed from the density dependence of the activation free energy in the Adam-Gibbs relation, is consistent with the exponent values obtained by other means.