Grain boundary scars and spherical crystallography.

Bausch, A R; Bowick, M J; Cacciuto, A; Dinsmore, A D; Hsu, M F; Nelson, D R; Nikolaides, M G; Travesset, A et al. · Science · 2003

basic_science · Level V

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Abstract

We describe experimental investigations of the structure of two-dimensional spherical crystals. The crystals, formed by beads self-assembled on water droplets in oil, serve as model systems for exploring very general theories about the minimum-energy configurations of particles with arbitrary repulsive interactions on curved surfaces. Above a critical system size we find that crystals develop distinctive high-angle grain boundaries, or scars, not found in planar crystals. The number of excess defects in a scar is shown to grow linearly with the dimensionless system size. The observed slope is expected to be universal, independent of the microscopic potential.