Discontinuous Interface Depinning from a Rough Wall

Abstract

Depinning of an interface from a random self--affine substrate with roughness exponent ${\zeta }_S$ is studied in systems with short--range interactions. In 2$D$ transfer matrix results show that for ${\zeta }_S<1/2$ depinning falls in the universality class of the flat case. When ${\zeta }_S$ exceeds the roughness (${\zeta }_0=1/2$) of the interface in the bulk, geometrical disorder becomes relevant and, moreover, depinning becomes \underline{discontinuous}. The same unexpected scenario, and a precise location of the associated tricritical point, are obtained for a simplified hierarchical model. It is inferred that, in 3$D$, with ${\zeta }_0=0$, depinning turns first--order already for ${\zeta }_S>0$. Thus critical wetting may be impossible to observe on rough substrates.

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References in corpus (1)

• Solid--on--Solid Model for Adsorption on Self--Affine Substrate: A Transfer Matrix Approach

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