Crystal-liquid interfacial free energy of hard spheres via a novel thermodynamic integration scheme

TL;DR

This paper introduces a new thermodynamic integration method using Gaussian flat walls to accurately compute the crystal-liquid interfacial free energy of hard spheres, effectively avoiding hysteresis and finite-size effects.

Contribution

The novel TI scheme successfully circumvents hysteresis effects in interfacial free energy calculations using short-ranged walls, improving accuracy over previous methods.

Findings

The new TI scheme reduces hysteresis in simulations.

Finite-size effects are significant and must be analyzed.

Reliable estimates of interfacial free energy require finite-size correction.

Abstract

The hard sphere crystal-liquid interfacial free energy, ($\gamma_{\rm cl}$), is determined from molecular dynamics simulations using a novel thermodynamic integration (TI) scheme. The advantage of this TI scheme compared to previous methods is to successfully circumvent hysteresis effects due to the movement of the crystal-liquid interface. This is accomplished by the use of extremely short-ranged and impenetrable Gaussian flat walls which prevent the drift of the interface while imposing a negligible free-energy penalty. We find that it is crucial to analyze finite-size effects in order to obtain reliable estimates of $\gamma_{\rm cl}$ in the thermodynamic limit.