Nucleation barriers in tetrahedral liquids spanning glassy and crystallizing regimes

TL;DR

This study uses computer simulations to analyze nucleation barriers in tetrahedral liquids, revealing how bond angles influence glass formation and crystallization, and identifying conditions that optimize nucleation.

Contribution

It demonstrates how changing bond angles in a tetrahedral model affects nucleation barriers and crystallization, providing insights into controlling glassy versus crystalline states.

Findings

Nucleation barriers depend on bond angle and temperature.

Optimal patch size facilitates easier crystallization.

Barrier heights are similar for diamond and stacking crystal forms.

Abstract

Crystallization and vitrification of tetrahedral liquids are important both from a fundamental and a technological point of view. Here, we study via extensive umbrella sampling Monte Carlo computer simulations the nucleation barriers for a simple model for tetrahedral patchy particles in the regime where open tetrahedral crystal structures (namely cubic and hexagonal diamond and their stacking hybrids) are thermodynamically stable. We show that by changing the angular bond width, it is possible to move from a glass-forming model to a readily crystallizing model. From the shape of the barrier we infer the role of surface tension in the formation of the crystalline clusters. Studying the trends of the nucleation barriers with the temperature and the patch width, we are able to identify an optimal value of the patch size that leads to easy nucleation. Finally, we find that the nucleation barrier is the same, within our numerical precision, for both diamond crystals and for their stacking forms.