Multistep Crystallization of the Heteroepitaxially Grown Binary Colloidal Crystals

Binary colloidal crystals (BCCs) offer broad application potential due to their tunable characteristics and serve as valuable model systems for studying atomic crystallization processes. Understanding nonclassical nucleation and growth behavior has recently garnered significant interest in this field. In this study, we examine BCC nucleation via heteroepitaxial growth, where BCCs form on a foreign unary colloidal crystal surface. This process promotes metastable phase formation, resulting in a multistep nucleation pathway characteristic of nonclassical nucleation, ultimately transitioning into the most thermodynamically favored phase. Particle-resolved in situ observations reveal composition-dependent nucleation dynamics, with variations in nucleation rate, growth rate, and final products based on composition. These insights advance the controlled growth of BCCs and contribute to a deeper understanding of complex crystallization mechanisms in multicomponent atomic systems.