Correlated Membrane Fluctuations in Nanocrystal Superlattices.
Superlattices of organic monolayer-stabilized silver nanocrystals exhibit structural integrity at temperatures well above the melting point of the hydrocarbon capping ligands (i.e., the C (8), C (12), and C (16) alkanethiols used in this study). Temperature-dependent small angle x-ray scattering reveals that topological disordering occurs with spatially correlated domains of characteristic length xi that grow with increasing temperature until xi diverges at a critical temperature T(c), as xi approximately xi(0)(1-T/T(c))(-0.67). A power law analysis of the scattering intensity with wave vector indicates that interactions between membranes due to thermal undulations control the topology below T(c).
Korgel
BA
Department of Chemical Engineering and Texas Materials Institute, and Center for Nano- and Molecular Science and Technology, The University of Texas, Austin, Texas 78712-1062.