Dynamics of a driven surface.
We present a Monte Carlo study of an Edwards-Wilkinson type of surface when it is driven by another random surface which drifts with a rate 0<phi<1. When it is driven by another drifting surface, it is shown to be of the Kardar-Parisi-Zhang (KPZ) type; we show that the asymptotic drift of its center of mass is preceded by a subdiffusive regime characterized by an effective exponent whose value is slightly less than that of the KPZ growth exponent (beta=1/3) because of slow crossover. Our numerical study demonstrates that the growth of fluctuations for the driven surface shows an extremely slow crossover to the KPZ regime observable only for very large system sizes. The equilibrium fluctuation of the surface exhibits a minimum at a certain driving rate phi*, which separates the regimes of entropic repulsion and entropic compliance. Since our model of interacting surfaces is a generalization of the Brownian Ratchet model for protrusions of biological cell membranes, we discuss it vis-a-vis the standard load-velocity relationship, and we compare the present model membrane to cell membranes.
Narasimhan
S L
SL
Solid State Physics Division, Bhabha Atomic Research Center, Mumbai 400085, India.
Baumgaertner
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