Periodicity and atomic ordering in nanosized particles of crystals

Evidence is presented that nanosized particles of crystals do not necessarily adopt a periodic atomic structure as their bulk counterparts do and/or as predicted by theory. As an example, 1.6-nm Au particles grown inside a dendrimeric host are studied and found to possess a heavily disordered, metallic glass-type structure. The nanoparticle's structure evolves toward the face-centered-cubic-type lattice of bulk Au only upon removal of solvent. The results show that periodicity, which rules the structure and properties of bulk crystals, is less of a constraint at the nanoscale level and, therefore, may be used as tunable parameter in nanotechnology research.