| abstract |
Abstract
Deposition and evaporation of infinitely thin hard rods (interacting
via hard core repulsion) is studied in two dimensions using Monte Carlo simulations.
The ratio of deposition to evaporation rates controls the equilibrium density of rods.
Increasing this rate ratio leads to an entropy-driven transition to a nematic phase where
the rods tend to orient along a common direction. This oriented phase shows a
peculiar ordering which is analysed by studying the behaviour of order parameter
and orientational correlations. These correlations exhibit power law decay in space and time.
At coarse-grained level, the dynamics of the angle field is described by the
Edwards-Wilkinson equation.
We also explore the effects of spatial inhomogeneity in the deposition-evaporation ratio by
varying it along the 2D substrate. The primary effect is that the hard rods tend to
align along the local spatial gradient of the ratio. A gradient acting only in one direction
thus induces an aligned state. The simulations are substantiated by
entropy-based arguments and study of new terms introduced in the free energy.
Random variations of deposition-evaporation rates in both directions induce frustration,
resulting in a state with characteristics of a glassy system.