Computer simulation studies of finite-size broadening of solid-liquid interfaces: From hard spheres to nickel

TL;DR

This study uses molecular dynamics and Monte Carlo simulations to analyze how finite system sizes affect the broadening of solid-liquid interfaces in hard spheres and nickel, confirming capillary wave theory predictions and estimating interfacial stiffness.

Contribution

It provides a comparative analysis of interfacial properties in hard sphere and nickel systems using order parameters and finite-size scaling, advancing understanding of interfacial broadening.

Findings

Interfacial width diverges logarithmically with system size.

Interfacial stiffness estimated as 0.5 k_B T/σ^2 for hard spheres.

Interfacial stiffness estimated as 0.18 J/m^2 for nickel.

Abstract

Using Molecular Dynamics (MD) and Monte Carlo (MC) simulations interfacial properties of crystal-fluid interfaces are investigated for the hard sphere system and the one-component metallic system Ni (the latter modeled by a potential of the embedded atom type). Different local order parameters are considered to obtain order parameter profiles for systems where the crystal phase is in coexistence with the fluid phase, separated by interfaces with (100) orientation of the crystal. From these profiles, the mean-squared interfacial width w^2 is extracted as a function of system size. We rationalize the prediction of capillary wave theory that w^2 diverges logarithmically with the lateral size of the system. We show that one can estimate the interfacial stiffness from the interfacial broadening, obtaining 0.5 k_B T/sigma^2 for hard spheres and 0.18 J/m^2 for Ni.