Elastic Instability of a Crystal Growing on a Curved Surface
Image courtesy of Guangnan Meng and Vinothan N. Manoharan, Harvard University
Although the effects of kinetics on crystal growth are well understood, the role of substrate curvature is not yet established. Harvard Physics and SEAS researchers, including Associate of the Department of Physics Guangnan Meng and professors Manoharan and Nelson, studied rigid, two-dimensional colloidal crystals growing on spherical droplets to understand how the elastic stress induced by Gaussian curvature affects the growth pathway. In contrast to crystals grown on flat surfaces or compliant crystals on droplets, these crystals formed branched, ribbon-like domains with large voids and no topological defects. The researchers show that this morphology minimizes the curvature-induced elastic energy. Their results illustrate the effects of curvature on the ubiquitous process of crystallization, with practical implications for nanoscale disorder-order transitions on curved manifolds, including the assembly of viral capsids, phase separation on vesicles, and crystallization of tetrahedra in three dimensions.