Phase ordering, transformation, and grain growth of two-dimensional binary colloidal crystals: A phase field crystal modeling

TL;DR

This study uses phase field crystal modeling to explore the formation, dynamics, and structural transformations of binary two-dimensional colloidal crystals, revealing key factors influencing their complex ordering and defect structures.

Contribution

It introduces a phase field crystal model with sublattice ordering to systematically analyze binary colloidal crystal structures and their transformation processes.

Findings

Identified coupling and competition between sublattice length scales as key factors in phase ordering.

Predicted various complex binary ordered patterns based on particle density and length scale ratios.

Compared model results with experimental colloidal system behaviors.

Abstract

The formation and dynamics of a wide variety of binary two-dimensional ordered structures and superlattices are investigated through a phase field crystal model with sublattice ordering. Various types of binary ordered phases, the phase diagrams, and the grain growth dynamics and structural transformation processes, including the emergence of topological defects, are examined. The results are compared to the ordering and assembly of two-component colloidal systems. Two factors governing the binary phase ordering are identified, the coupling and competition between the length scales of two sublattices and the selection of average particle densities of two components. The control and variation of these two factors lead to the prediction of various complex binary ordered patterns, with different types of sublattice ordering for integer vs. noninteger ratios of sublattice length scales. These findings will enable further systematic studies of complex ordering and assembly processes of binary systems particularly binary colloidal crystals.