Mobile particles in an immobile environment: Molecular dynamics simulation of a binary Yukawa mixtureN. Kikuchi and J. Horbach
Institut für Physik, Johannes Gutenberg-Universität Mainz - Staudingerweg 7, D-55099 Mainz, Germany
received 5 September 2006; accepted in final form 14 November 2006; published January 2007
published online 9 January 2007
Molecular dynamics computer simulations are used to investigate the dynamics of a binary mixture of charged (Yukawa) particles with a size ratio of 1 : 5. We find that the system undergoes a phase transition where the large particles crystallize while the small particles remain in a fluid-like (delocalized) phase. Upon decreasing temperature below the transition, the small particles become increasingly localized on intermediate time scales. This is reflected in the incoherent intermediate scattering functions by the appearance of a plateau with a growing height. At long times, the small particles show a diffusive hopping motion. We find that these transport properties are related to structural correlations and to the single-particle potential energy distribution of the small particles.
61.20.Lc - Time-dependent properties; relaxation .
66.30.Hs - Self-diffusion and ionic conduction in nonmetals .
61.43.Er - Other amorphous solids .
© Europhysics Letters Association 2007