Atomistically informed melting models for aluminum nanocrystals

Abstract

Atomistically informed analysis of melting is conducted to predict equilibrium melting points of aluminum nanocrystals in the size range 2–10 nm. Spherical and cubic nanocrystals and planar films are considered. Relevant properties are calculated using atomistic simulations and fed as inputs to thermodynamic models. Bulk melting point is calculated using solid-liquid coexistence simulations, while surface free energies are obtained using thermodynamic integration approach. Solid phase density and latent heat of melting are calculated using atomistic simulations of infinite bulk. Melting points are also computed using atomistic melting simulations. Care is taken to minimize superheating and detect onset of melting accurately. Qualitative agreement between predictions of atomistic simulations and thermodynamic models is achieved. Some interesting trends regarding size and orientation dependencies of melting points are reported. Studying radial variations of the potential energy is an effective and consistent way to detect the onset of melting for all particle sizes.