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

The hard-sphere crystal-liquid interfacial free energy gamma(cl) is determined from molecular dynamics simulations using a 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-range and impenetrable Gaussian flat walls that 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(cl) in the thermodynamic limit.