Correlated disorder in entropic crystals

Abstract

We report computational evidence of a new type of disordered phase in crystals resulting from entropy driven self-assembly of hard convex polyhedra. The disorder was reflected in the orientations of the anisotropic particles and not in the positions of the centers of geometry. Despite the lack of order, particle orientations were not random and exhibited strong correlations. The correlations were manifested in terms of ``quantized'' rotational motions in a fixed number of absolute orientations, while maintaining equal populations and specific measure of pairwise angular differences among the discrete values. This gave rise to a discretely mobile phase in the low density solid and a quenched disordered state at high pressure. This finding can be interpreted as the simplest example of correlated disorder in crystalline materials.Comment: 15 pages, 4 figures in the main text, 11 figures in the supporting informatio