Elastically Disordered Perfect Colloidal Crystals

ORAL

Abstract

We use spherical microgel colloidal particles to study lattice dynamics in a three-dimensional crystal using optical microscopy. We find that the local bond length fluctuations vary by as much as 75{\%} from bond to bond despite less than 2{\%} fluctuations in the equilibrium bond lengths. We show how to calculate the low-energy eigenmodes and the density of states in the presence of the strong heterogeneity. We find that the lowest energy eigenmodes are dominated by a few long-wavelength planewaves, and the density of states shows Debye-like behavior at low energy. This work has been partially supported by the NSF through Grants DMR-0619424 and DMR-0645596, by ACS-PRF and Alfred P. Sloan foundation.

–

Authors

  • Deniz Kaya

    • Department of Chemical Engineering

  • N.L. Green

    • Department of Chemical Engineering

  • C.E. Maloney

    • Carnegie Mellon
    • Carnegie Mellon University
    • Department of Civil \& Environmental Engineering
    • Deparment of Civil and Environmental Engineering

  • M.F. Islam

    • Department of Chemical Engineering and Department of Materials Science \& Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
    • Departments of Chemical Engineering, Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213