Metallization of colloidal crystals*

Size asymmetric binary colloidal crystals with structures analogous to ionic atomic crystals undergo a transition where the smaller component delocalizes as the temperature increases, generating "metallic" colloidal crystals. The small particles roam among the large particles holding together the lattice, as electrons do in metals. In this talk, I will describe the nature of this localized-delocalized sublattice transition in size asymmetric colloidal mixtures and make analogies with an insulator-metal transition that is largely driven by phonons of different crystal phases.