A quantitative theory and atomistic simulation study on the soft-sphere crystal-melt interfacial properties: II. Interfacial free energies

Abstract: This study proposes a new method for predicting the crystal-melt interfacial free energy ($\gamma$) using the Ginzburg-Landau (GL) model, enhanced by atomistic simulation data for more accurate density wave profiles. The analysis focuses on the soft-sphere system governed by an inverse power potential that stabilizes both BCC and FCC phases. Equilibrium molecular dynamics (MD) simulations are used to obtain density wave amplitude distributions, which serve as inputs for the GL model to predict $\gamma$ and its anisotropy. The predicted $\gamma$ values exhibit strong agreement with prior benchmark simulation experimental studies, particularly for FCC crystal-melt interfaces (CMIs). The GL models for the CMI $\gamma$ are proved to be both computationally efficient and reasonably valid, offering quantitative predictions of $\gamma$ while providing insights into the factors controlling its magnitude and anisotropy. Key improvement is suggested for the variational procedure used in the two-mode CMI free energy functionals, and potential upgrades to the GL model are also proposed to further enhance predictive accuracy.