Line-slip defects in colloidal crystals on a cylinder

ORAL

Abstract

We study crystallization of colloidal spheres on the surface of a cylinder. Because a cylinder has zero Gaussian curvature and can accommodate a finite number of particles around its circumference, different crystalline structures assemble, depending on the ratio of the particle size to cylinder size. When a perfect crystal cannot be accommodated, the densest packing is achieved by having a line-slip defect, Such defects consist of a line of particles, each of which has one fewer contact than in bulk. We study these defects with an experimental system consisting of submicron-sized colloidal spheres that assemble into hexagonal lattices on a drawn silica fiber with a diameter of a few microns. The assembly is driven by a short-ranged depletion interaction. By varying the ratio of the sphere size to the fiber diameter, we find crystals with different chirality and line-slip structure. We find ground state line slips with one straight helical line, but also a new type of line slip with kinks. We see that some of the kinks disappear over time and reach the ground state of straight line slips. To explain this experimental observation, we perform finite temperature simulations on the system and find that the kinks represent low energy excitations of the system.

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Presenters

  • Nabila Tanjeem

    Harvard University, Applied Physics, Harvard University

Authors

  • Nabila Tanjeem

    Harvard University, Applied Physics, Harvard University

  • Henry Wilkin

    Harvard University

  • Daniel Beller

    brown university, School of Engineering, Brown University, Brown University

  • Christopher Rycroft

    SEAS, Harvard Univ, Harvard University, SEAS, Harvard University, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Harvard Univ, Paulson School of Engineering and Applied Sciences, Harvard University, Applied Mathematics, Harvard University

  • Vinothan Manoharan

    School of Engineering and Applied Sciences, Harvard University, Harvard Univ, Harvard University, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Physics and Chemical Engineering, Harvard University