Diffusion dynamics and steady states of systems of hard rods on the square lattice

Abstract

It is known from grand canonical simulations of a system of hard rods on two dimensional lattices that an orientationally ordered nematic phase exists only when the length of the rods is at least seven. However, a recent microcanonical simulation with diffusion kinetics, conserving both total density and zero nematic order, reported the existence of a nematically phase segregated steady state with interfaces in the diagonal direction for rods of length six [Phys. Rev. E 95, 052130 (2017)], violating the equivalence of different ensembles for systems in equilibrium. We resolve this inconsistency by demonstrating that the kinetics violate detailed balance condition and drives the system to a nonequilibrium steady state. By implementing diffusion kinetics that drives the system to equilibrium, even within this constrained ensemble, we recover earlier results showing phase segregation only for rods of length greater than or equal to seven. Furthermore, in contrast to the nonequilibrium steady state, the interface has no preferred orientational direction. In addition, by implementing different nonequilibrium kinetics, we show that the interface between the phase segregated states can lie in different directions depending on the choice of kinetics.

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Cited by in corpus (6)

• Two-dimensional systems of elongated particles: From diluted to dense
• Quantifying nematic order in evaporation-driven self-assembly of Halloysite nanotubes: Nematic islands and critical aspect ratio
• Microemulsions in the driven Widom-Rowlinson lattice gas
• Characterisation of diffusion-driven self-organisation of rodlike particles by means of entropy of generalised two-dimensional words
• Monte Carlo simulation of entropy-driven pattern formation in two-dimensional system of rectangular particles
• Impact of packing fraction on diffusion-driven pattern formation in a two-dimensional system of rod-like particles