Eur. Phys. J. B 38, 71-82 (2004)
https://doi.org/10.1140/epjb/e2004-00101-6

From weak to strong pinning I: A finite size study

Laboratoire de Physique de la Matière Condensée et des Nanostructures, Université de Lyon I, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne, France

Corresponding author: ^a atanguy@lpmcn.univ-lyon1.fr

Received: 3 February 2003
Revised: 12 September 2003
Published online: 20 April 2004

Abstract

We have used linear stability analysis to study the depinning of an elastic chain with long range interactions submitted to a random pinning potential. In this paper, we provide, for the first time, evidence of a pronounced change from a strong pinning regime to a weak pinning regime. This change depends on the strength of disorder, and takes place only in finite size systems. For a given disorder, we show a characteristic length separating the weak pinning regime from the strong pinning regime. This length depends on the long range of the algebraic decay of the elastic couplings. The weak pinning regime is very well described by perturbation theory. As an example, we discuss more specifically the case of wetting of heterogeneous surfaces, where the change from a strong to a weak pinning regime could be induced in the wetting front by varying the surface tension of the liquid-air interface.