Devitrification of the Kob-Andersen glass former: Competition with the locally favored structure

TL;DR

This study investigates how biasing the local structure population in the Kob-Andersen glass former influences crystallization, revealing insights into the competition between local and global order in glass-forming liquids.

Contribution

It demonstrates that biasing towards fewer locally favored structures induces crystallization, providing a microscopic understanding of devitrification in glass formers.

Findings

Bias towards small locally favored structure population induces crystallization.

Estimated free energy difference related to local structure bias.

Revealed competition between local and global order in glass-forming liquids.

Abstract

Supercooled liquids are kinetically trapped materials in which the transition to a thermodynamically more stable state with long-range order is strongly suppressed. To assess the glass-forming abilities of a liquid empirical rules exist, but a comprehensive microscopic picture of devitrification is still missing. Here we study the crystallization of a popular model glass former, the binary Kob-Andersen mixture, in small systems. We perform trajectory sampling employing the population of the locally favored structure as order parameter. While for large population a dynamical phase transition has been reported, here we show that biasing towards a small population of locally favored structures induces crystallization, and we estimate the free energy difference. This result sheds new light on the competition between local and global structure in glass-forming liquids and its implications for crystallization.