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

TL;DR

This paper investigates the depinning transition of interfaces in the 3D random-field Ising model using Monte Carlo simulations, revealing how overhangs influence critical behavior and providing new scaling relations.

Contribution

Introduces a novel algorithm for simulating interfaces in the RFIM across dimensions and time scales, and analyzes the impact of overhangs on the depinning transition.

Findings

Critical exponents for velocity, correlation length, and thermal rounding.

Numerical evidence for a scaling relation involving system dimension.

Overhangs significantly affect the depinning transition characteristics.

Abstract

We analyze the depinning transition of a driven interface in the 3d random-field 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 introduce an algorithm which is capable of simulating such an interface independent of the considered dimension and time scale. This algorithm is applied to the 3d-RFIM to study both the depinning transition and the influence of thermal fluctuations on this transition. It turns out that in the RFIM characteristics of the depinning transition depend crucially on the existence of overhangs. Our analysis yields critical exponents of the interface velocity, the correlation length, and the thermal rounding of the transition. We find numerical evidence for a scaling relation for these exponents and the dimension d of the system.