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Center for Nonlinear Studies |
We examine pattern formation of colloids atop a square periodic substrate using large scale numerical simulations. The pins forming the substrate are modeled with a muffin-tin potential which is flat with localized traps. We show that with 4 colloids per pinning site the system has triangular ordering and with 5 colloids per site it has square ordering. We study intermediate fillings and identify a rich variety of distinct ordering regimes including disordered grain boundaries, crystalline stripe structures, superlattice orderings, and disordered patches of multiple phases. We also apply a drive to the system, and show that several dynamically ordered states arise. Our results show that periodic substrates of muffin-tin potentials can be used to tailor grain boundary formation.
Host: Cynthia Reichhardt, T-1, 665-1134