Phase-field crystal modelling of crystal nucleation, heteroepitaxy and patterning

TL;DR

This paper uses the phase-field-crystal model to study crystal nucleation, heteroepitaxy, and patterning, revealing new insights into nucleation processes and substrate effects in colloidal and metallic systems.

Contribution

It demonstrates the application of the PFC model to heterogeneous nucleation, amorphous precursors, and patterning, providing novel predictions beyond classical theories.

Findings

Homogeneous nucleation occurs without hexatic phase in 2d supersaturated liquids.

Amorphous precursors appear before crystallization at high supersaturation.

Corners are not always favorable for nucleation, contrary to classical expectations.

Abstract

We apply a simple dynamical density functional theory, the phase-field-crystal (PFC) model, to describe homogeneous and heterogeneous crystal nucleation in 2d monodisperse colloidal systems and crystal nucleation in highly compressed Fe liquid. External periodic potentials are used to approximate inert crystalline substrates in addressing heterogeneous nucleation. In agreement with experiments in 2d colloids, the PFC model predicts that in 2d supersaturated liquids, crystalline freezing starts with homogeneous crystal nucleation without the occurrence of the hexatic phase. At extreme supersaturations crystal nucleation happens after the appearance of an amorphous precursor phase both in 2d and 3d. We demonstrate that contrary to expectations based on the classical nucleation theory, corners are not necessarily favourable places for crystal nucleation. Finally, we show that adding external potential terms to the free energy, the PFC theory can be used to model colloid patterning experiments.