Crystal growth kinetics of barium sulfide (BaS): insights from molecular dynamics and kinetic phase-field modeling

The growth of the semiconductor compound barium sulfide (BaS) is being studied using atomistic methods and mesoscopic theoretical modeling. Material properties such as phase densities, enthalpies, specific latent heat, Gibbs free energy difference, liquid diffusion coefficient, interfacial free energies, and stiffness for different crystal faces of the crystal lattice of BaS are obtained by molecular dynamics (MD). The growth kinetics studied by the MD method show close to linear growth velocity dependence in the range of undercoolingΔT<800 K with a slight abnormal acceleration bend caused by the nucleation of crystals in the bulk liquid. The hodograph equation, as the sharp interface limit of the kinetic phase field (KPF) and as the mesoscopic approach to modeling, well predicts the growth kinetics of crystal phases in BaS atΔT<500 K and the whole tendency of growth kinetics atΔT>500 K. The discussion on the non-linear behavior of the dynamic diffuse interface of BaS crystal faces width is given upon predictions by MD and KPF methods.