Microdiffusion in (2 + 1)-dimensional chain-bundle dusty-plasma liquids.

Microdiffusion in a (2 + 1)-dimensional liquid with flexible long longitudinal chain bundles, formed by negatively charged dusts suspended in a low-pressure Ar gaseous discharge, is investigated. With increasing time scale τ, the transverse hopping dominated displacement induces the transition from the sub- to the superdiffusion of the single dust, and the growth of spatial displacement correlation of two dusts, which suppresses their relative diffusion. The rise time of displacement correlation increases with dust separation. The bond breaking around the hopping cluster boundary is the main source for long time relative diffusion and causes the presence of the multiple shoulders in the fat tails of the non-Gaussian relative displacement histograms. The stronger longitudinal coupling than the transverse coupling strongly enhances the motion correlation over much larger separation, and suppresses the bond-breaking rate and the relative diffusion of the longitudinal dust pairs.