Title: Morphology dictated heterogeneous dynamics in two-dimensional aggregates
Speaker: Dr. Tamoghna Das, University of Maryland, USA
Venue: IOP Lecture Hall
Date: 2016-Aug-23 11:00:00
Abstract: Two-dimensional (2D) particulate aggregates formed due to
competing interactions exhibit a range of non-equilibrium steady state
morphologies from finite-size compact crystalline structures to
non-compact string-like conformations. We report a transition in
heterogeneous microscopic dynamics across this morphological hierarchy as
a function of decreasing long-range repulsion relative to short-range
attraction at a constant low density and temperature. Following a `slow'
cooling protocol to form steady state aggregates, we show that geometric
frustration inherent to competing interactions assures non-ergodicity of
the system, which in turn results in long-time sub diffusive relaxation.
Analyzing individual particle trajectories generated by molecular
dynamics, we identify caging dynamics of particles in compact clusters in
contrast to the bonding scenario for non-compact ones. Finally, by
monitoring temperature dependence of the same fixed density system, we
present a generic relation between diffusivity and structural randomness
of the aggregates, irrespective of their thermodynamic equilibrium.
