Template induced precursor formation in heterogeneous nucleation -- Controlling polymorph selection and nucleation efficiency

TL;DR

This study uses atomistic simulations to show how tiny templates influence the formation of precursor regions with specific order, thereby controlling polymorph selection and nucleation efficiency in Ni.

Contribution

It uncovers a template precursor-mediated mechanism of heterogeneous nucleation and links liquid heterogeneity to nucleation efficiency and polymorph outcomes.

Findings

Tiny templates modify liquid structure and promote precursor regions.

Template effectiveness depends on structural features of the liquid.

Results advance understanding of controlling nucleation and polymorph selection.

Abstract

We present an atomistic study of heterogeneous nucleation in Ni employing transition path sampling, which reveals a template precursor-mediated mechanism of crystallization. Most notably, we find that the ability of tiny templates to modify the structural features of the liquid and promote the formation of precursor regions with enhanced bond-orientational order is key to determine their nucleation efficiency and the polymorphs that crystallize. Our results reveal an intrinsic link between liquid heterogeneity and the nucleating ability of templates, which significantly advances our understanding towards the control of nucleation efficiency and polymorph selection.