Phase behavior of hard colloidal bipyramid family

Colloidal particles with bipyramidal shape are experimentally obtainable today, and some of them are known to self-assemble into highly complex crystals such as clathrates and quasicrystals by maximizing face-to-face alignment, e.g. via DNA-programmable assembly or via entropy maximization. We present a study of the effect of shape variation on the self-assembly of hard bipyramids using Monte Carlo simulation. We report the phase behavior as a function of the number of vertices in the base polygon and the aspect ratio. From geometric and thermodynamic analysis, we identified over 10 different crystalline structures with varying complexity and symmetry. Our results offer guidance to experiments by providing information about entropically driven self-assembly in the bipyramidal shape family.