Dislocation reactions, grain boundaries, and irreversibility in two-dimensional lattices using topological tweezers

William T.M. Irvine, Andrew D. Hollingsworth, David G. Grier, Paul M. Chaikin

    Research output: Contribution to journalArticle


    Dislocations, disclinations, and grain boundaries are topological excitations of crystals that play a key role in determining outof- equilibrium material properties. In this article we study the kinetics, creation, and annihilation processes of these defects in a controllable way by applying topological tweezers, an array of weak optical tweezers which strain the lattice by weakly pulling on a collection of particles without grabbing them individually. We use topological tweezers to deterministically control individual dislocations and grain boundaries, and reversibly create and destroy dislocation pairs in a 2D crystal of charged colloids. Starting from a perfect lattice, we exert a torque on a finite region and follow the complete step-by-step creation of a disoriented grain, from the creation of dislocation pairs through their reactions to form a grain boundary and their reduction of elastic energy. However, when the grain is rotated back to its original orientation the dislocation reactions do not retrace. Rather, the process is irreversible; the grain boundary expands instead of collapsing.

    Original languageEnglish (US)
    Pages (from-to)15544-15548
    Number of pages5
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number39
    StatePublished - Sep 24 2013



    • Colloidal crystal
    • Holographic trapping
    • Topological defect

    ASJC Scopus subject areas

    • General

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