Kinetics of Crystallization and Orientational Ordering in Dipolar Particle Systems

The kinetic mechanisms underlying bottom-up assembly of colloidal particles have been widely investigated in efforts to control crystallization pathways and to direct growth into targeted superstructures for applications including photonic crystals. Current work builds on recent progress in the development of kinetic theories for crystal growth of body-centered-cubic crystals in systems with short-range inter-particle interactions, accounting for a greater diversity of crystal structures and the role of the longer-ranged interactions and orientational degrees of freedom arising in polar systems. We address the importance of orientational ordering processes in influencing crystal growth in such polar systems, thus advancing the theory beyond the treatment of the translational ordering processes considered in previous investigations. The work employs comprehensive molecular-dynamics simulations that resolve key crystallization processes, and are used in the development of a quantitative theoretical framework based on ideas from time-dependent Ginzburg-Landau theory. The significant impact of orientational ordering on the crystallization kinetics could be potentially leveraged to achieve crystallization kinetics steering through external electric or magnetic fields. Our combined theory/simulation approach provides opportunities for future investigations of more complex crystallization kinetics.

Xian-Qi Xu, Brian B. Laird, Jeffrey J. Hoyt, Mark Asta, Yang Yang · 2020