Interplay of interfacial noise and curvature driven dynamics in two dimensions

Abstract

We explore the effect of interplay of interfacial noise and curvature driven dynamics in a binary spin system. An appropriate model is the generalised two dimensional voter model proposed earlier (J. Phys. A: Math. Gen. {\bf 26}, 2317 (1993)), where the flipping probability of a spin depends on the state of its neighbours and is given in terms of two parameters $x$ and $y$. $x = 0.5, y =1$ corresponds to the conventional voter model which is purely interfacial noise driven while $x = 1 $ and $y = 1$ corresponds to the Ising model, where coarsening is fully curvature driven. The coarsening phenomena for $0.5< x < 1$ keeping $y=1$ is studied in detail. The dynamical behaviour of the relevant quantities show characteristic differences from both $x=0.5$ and $1$. The most remarkable result is the existence of two time scales for $x\ge x_c$ where $x_c \approx 0.7$. On the other hand, we have studied the exit probability which shows Ising like behaviour with an universal exponent for any value of $x > 0.5$; the effect of $x$ appears in altering the value of the parameter occurring in the scaling function only.