Size-dependent defect redistribution during melting of monolayer crystalline clusters

The melting of finite-sized two-dimensional (2D) clusters is ubiquitous in nature and technology. Here, we reveal a sequential surface-to-bulk-to-surface redistribution of defects in large clusters, whereas defects remain predominantly surface-localised in small crystallites. Using molecular dynamics simulations of colloids with tunable interactions, which serve as molecular-like model systems, we study the spatial distribution of defects and observe pronounced size-dependent defect behaviour during melting. Our results shed light on the role of cluster size in defect formation and melting across systems ranging from atomic clusters to colloidal assemblies.