Interface motion in random media at finite temperature.

We have studied numerically the dynamics of a driven elastic interface in a random medium, focusing on the thermal rounding of the depinning transition and on the behavior in the T = 0 pinned phase. Thermal effects are quantitatively more important than expected from simple dimensional estimates. For sufficient low temperature the creep velocity at a driving force equal to the T = 0 depinning force exhibits a power-law dependence on T , in agreement with earlier theoretical and numerical predictions for CDW's. We have also examined the dynamics in the T = 0 pinned phase resulting from slowly increasing the driving force towards threshold. The distribution of avalanche sizes S decays as S −1−κ , with κ = 0.05 ± 0.05, in agreement with recent theoretical predictions.