Creep Motion of an Elastic String in a Random Potential

ALEJANDRO B. KOLTON, ALBERTO ROSSO, AND THIERRY GIAMARCHI

PHYSICAL REVIEW LETTERS

The American Physical Society

Lugar: USA; Año: 2005 vol. 94 p. 47002 - 47006

0031-9007

We study the creep motion of an elastic string in a two-dimensional pinning landscape by means of Langevin dynamics simulations. We find that the velocity-force characteristics are well described by the creep formula predicted from phenomenological scaling arguments. We analyze the creep exponent µ and the roughness exponent . Two regimes are identified: when the temperature is larger than the strength of the disorder, we find µ1/4 and 2/3, in agreement with the quasi-equilibrium-nucleation picture of creep motion; on the contrary, when lowering the temperature enough, the values of µ and increase, showing a strong violation of the latter picture.