Depinning transition and thermal fluctuations in the random-field Ising model

We analyze the depinning transition of a driven interface in the three-dime nsional (3D) random held Ising model (RFIM) with quenched disorder by means of Monte Carlo simulations. The interface initially built into the system is perpendicular to the [111] direction of a simple cubic lattice. We intro duce an algorithm which is capable of simulating such an interface independ ent of the considered dimension and time scale. This algorithm is applied t o the 3D RFIM to study both the depinning transition and the influence of t hermal fluctuations on this transition. It turns out that in the RFIM chara cteristics of the depinning transition depend crucially on the existence of overhangs. Our analysis yields critical exponents of the interface velocit y, the correlation length, and the thermal rounding of the transition. We f ind numerical evidence far a scaling relation for these exponents and the d imension d of the system. [S1063-651X(99)03011-1].