Role of Lu and La in the intergranular films on growth of the prism surface in β-Si₃N₄: A molecular dynamics study

The different roles of Lu and La in the intergranular film in silicon nitride on the growth morphology are investigated via molecular dynamics simulations. While advanced microscopy shows each rare earth on the prism surface at room temperature, each additive affects the outward (perpendicular) growth of the surface differently. The simulations show the effect of elevated temperature on the adsorption of La and Lu on this surface that affects growth and provides the atomistic mechanism for the different growth morphology. - Graphical abstract: At elevated temperature, Lu ions move away from the surface as it grows, but remain in near contact (a-start, b-end), whereas La ions remain at the surface and prevent growth (c-start, d-end).