The correlation between fragility, density and atomic interaction in glass-forming liquids

TL;DR

This study uses molecular dynamics simulations to explore how atomic interactions and density influence the fragility of glass-forming liquids, revealing distinct dynamic regimes and the structural impact of attractions.

Contribution

It uncovers three dynamic regimes in purely repulsive systems and links fragility variations to structural properties and density effects.

Findings

Fragility landscape can be divided into three regions with different behaviors.

Density influences the steepness dependence of fragility unexpectedly.

Attractive interactions affect fragility through structural properties of zero-temperature glasses.

Abstract

The fragility, that controls the temperature-dependent viscous properties of liquids as the glass transition is approached, in various glass-forming liquids with different atomic interactions and densities is investigated by molecular dynamic simulations. We show the landscape of fragility in purely repulsive systems can be separated into three regions with qualitatively disparate dynamic behaviors, suggesting that the density plays an unexpected role for understanding the repulsive steepness dependence of fragility. Furthermore, the vastly dissimilar influences of attractive interaction on fragility could be estimated from the structural properties of related zero-temperature glasses