Softness suppresses fivefold symmetry and enhances crystallization of binary Laves phases in nearly hard spheres

Abstract

Colloidal crystals with a diamond and pyrochlore structure display wide photonic band gaps at low refractive index contrasts. However, these low-coordinated and open structures are notoriously difficult to self-assemble from colloids interacting with simple pair interactions. To circumvent these problems, one can self-assemble both structures in a closely packed MgCu2 Laves phase from a binary mixture of colloidal spheres and then selectively remove one of the sublattices. Although Laves phases have been proven to be stable in a binary hard-sphere system, they have never been observed to spontaneously crystallize in such a fluid mixture in simulations nor in experiments of micron-sized hard spheres due to slow dynamics. Here we demonstrate, using computer simulations, that softness in the interparticle potential suppresses the degree of fivefold symmetry in the binary fluid phase and enhances crystallization of Laves phases in nearly hard spheres.

References in corpus (9)

• Accurate determination of crystal structures based on averaged local bond order parameters
• Strong scaling of general-purpose molecular dynamics simulations on GPUs
• Finite-size corrections to the free energy of crystalline solids
• Identification of structure in condensed matter with the topological cluster classification
• Hiding in plain view: Colloidal self-assembly from polydisperse populations
• The role of shear in crystallization kinetics: From suppression to enhancement
• Complex Crystals from Size-disperse Spheres
• Crystallization of hard spheres revisited. II. Thermodynamic modeling, nucleation work, and the surface of tension
• Fabrication of colloidal Laves phases via hard tetramers and hard spheres: bulk phase diagram and sedimentation behaviour