(256b) Hard Superellipses: Phase Behavior & Structures

Tunable microstructures composed of colloidal building blocks are of great interest for technological applications and advanced materials such as photonic, negative refraction and controllable devices in emerging technologies, such as optical computing, sub-diffraction limit imaging, and invisibility cloaking. Current capabilities to produce such ordered materials with a sufficiently low defect density have limited the development of the science and applications of such materials. Thus, there is an interest in understanding how particle shape, particle interactions, and external fields can be coupled to control the assembly of colloidal components into reconfigurable materials.

In this work, we report results for the two-dimensional phase behavior of colloidal particles with superellipsoidal shape using Monte Carlo simulations. We analyze the phase behavior of a confined monolayer of superellipsoidal particles as a function of particle shape, particle aspect ratio, and particle concentration. We calculate phase behavior based on pair correlation functions, novel anisotropic local order parameters based on symmetry of near neighbors, and global order parameters based on positional and orientational order. The simulation results show that order parameters can be used to capture number of phases including liquids, liquid crystals, and a variety of crystal microstructures on hard superellipses with different aspect ratio.