Structural short-range forces between solid-melt interfaces

TL;DR

This paper predicts short-range structural interactions at solid-melt interfaces using amplitude equations derived from density functional theory, revealing how these interactions influence grain boundary premelting.

Contribution

It introduces an analytical approach to quantify the tail of solid-melt interface interactions based on amplitude equations, extending understanding of grain boundary behavior.

Findings

Interaction decays exponentially with interface thickness

Overlap of density wave profiles causes short-range interactions

Interaction decay is faster for misoriented grain boundaries

Abstract

We predict the structural interaction of crystalline solid-melt interfaces using amplitude equations which are derived from classical density functional theory or phase-field-crystal modeling. The solid ordering decays exponentially on the scale of the interface thickness at solid-melt interfaces; the overlap of two such profiles leads to a short range interaction, which is mainly carried by the longest-range density waves, which can facilitate grain boundary premelting. We calculate the tail of these interactions, depending on the relative translation of the two crystals fully analytically and predict the interaction potential, and compare it to numerical simulations. For grain boundaries the interaction is predicted to decay twice faster as for two crystals without misorientation.