Unconventionally Dynamical Regime of Colloidal Nanocrystals on Spherical Surfaces

Abstract Crystallography of colloidal nanocrystals on spherical surfaces underpins the structural organization of a wide range of functional soft and biological materials, from viral capsids and protein nanocages to colloidal microcapsules and curvature-engineered metamaterials. In these systems, the topology dictates that crystalline order on a sphere must incorporate topological defects that can self-organize into scars whose conformations undergo fluctuations. However, how these conformations collectively affect phase transitions on spheres remains unknown. Here, we investigate the phase transitions of colloidal nanocrystal packing on the spherical surface and identify an unconventional regime in the solid phase, which exhibits rapid dynamics with enhanced fluctuations of scars. Further analysis reveals that this regime is governed by the conformational entropy of the scars. Such an entropic effect on dynamics exhibits a nonmonotonic dependence on system size and causes disparate scaling laws at intermediate and large system sizes, which are absent in previous experiments and theoretical models. The findings provide insights into the effect of topological defects on curved manifolds and reveal the critical role of the conformational entropy of defect scars in geometrically frustrated systems of colloidal nanocrystals.