Phase behavior and crystal nucleation of hard triangular prisms

TL;DR

This study investigates the crystal nucleation process of hard triangular prisms, revealing that local density, positional, and orientational orderings increase simultaneously, with no detectable precursors, through Monte Carlo and brute force simulations.

Contribution

It provides the first detailed analysis of crystal nucleation in anisotropic particles, specifically hard triangular prisms, highlighting the simultaneous development of order parameters.

Findings

All local order parameters increase simultaneously during nucleation.

No precursor signals are observed before nucleus formation.

Nucleation barriers and coexistence values are quantitatively determined.

Abstract

The interplay between densification and positional ordering during the process of crystal nucleation is a greatly investigated topic. Even for the simplest colloidal model -- hard spheres -- there has been much debate regarding the potential foreshadowing of nucleation by significant fluctuations in either local density or local structure. Considering anisotropic particles instead of spheres adds a third degree of freedom to the self-organization process of crystal nucleation: orientational ordering. Here, we investigate the crystal nucleation of hard triangular prisms. Using Monte Carlo simulations, we first carefully determine the crystal-fluid coexistence values and calculate the nucleation barriers for two degrees of supersaturation. Next, we use brute force simulations to obtain a large set of spontaneous nucleation events. By studying the time evolution of the local density, positional ordering, and orientational ordering in the region in which the nucleus first arises, we demonstrate that all local order parameters increase simultaneously from the very start of the nucleation process. We thus conclude that we observe no precursor for the crystal nucleation of hard triangular prisms.