Two-phase core-shell nanoparticle model

A two-phase core-shell model for nanoparticle melting is proposed, in which a solid core is sur- rounded by a quasi-liquid shell. The model provides self-consistent analytical expressions for the size-depen- dent melting temperature and effective surface tension, along with kinetic equations describing the temporal evolution of the shrinking solid core under external heating. The analysis identifies distinct melting regimes, including a pronounced acceleration in the final stage caused by curvature-induced melting-point depression. Numerical estimates for silver and copper nanoparticles demonstrate that size effects can significantly reduce melting time. The results offer simple and physically transparent relations that clarify nanoscale melting behav- ior, provide an intuitive interpretation of the Tolman length, and explain the overheating observed in molecular dynamics simulations.

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