Crystal Structure and Interaction Dependence of the Crystal-Melt Interfacial Free Energy

We examine via molecular simulation the dependence of the crystal-melt interfacial free energy γ on molecular interaction and crystal structure (fcc vs bcc) for systems interacting with inverse-power repulsive potentials, u(r)=ϵ(σ/r)ⁿ, 6≤n≤100. Both the magnitude and anisotropy of γ are found to increase as the range of the potential increases. Also we find that γ_bcc<γ_fcc, consistent with recent observations that some fcc forming fluids nucleate via formation of metastable bcc nuclei. The anisotropy in γ is also seen to be smaller in the bcc systems. By extrapolation, we also obtain an improved estimate of γ for hard spheres.