Novel mesophase behavior in two-dimensional binary solid solutions

Abstract: Monte Carlo simulations were used to study the assembly of binary mixtures of hard disks with squares, where the components have size ratios that optimize their co-assembly into compositionally disordered solids. It is observed that, along with the enhanced regions of solid miscibility, a continuous-looking transition from the disk-like to the square-like behavior occurred through a novel mosaic (M) phase, which seamlessly bridges the regions of hexatic mesophase of disks and the tetratic mesophase of squares. The M phase has interspersed tetratic, hexatic, and rhombic-like locally ordered clusters.