Short-time domain-wall dynamics in the random-field Ising model with a driving field

TL;DR

This study uses Monte Carlo simulations to analyze the short-time dynamics of domain walls in a 2D random-field Ising model under a driving field, revealing non-universal scaling and anomalous behaviors.

Contribution

It provides a detailed analysis of the depinning transition and uncovers intrinsic anomalous scaling and multiscaling in the domain wall dynamics, challenging previous universality assumptions.

Findings

Determined the transition field and critical exponents accurately.

Observed intrinsic anomalous scaling and multiscaling behaviors.

Found that the interface does not belong to the Edwards-Wilkinson universality class.

Abstract

With Monte Carlo methods, we investigate the relaxation dynamics of a domain wall in the two-dimensional random-field Ising model with a driving field. The short-time dynamic behavior at the depinning transition is carefully examined, and the roughening process of the domain wall is observed. Based on the short-time dynamic scaling form, we accurately determine the transition field, static and dynamic exponents, and local and global roughness exponents. In contrast to the usual assumption, the results indicate that the domain interface does not belong to the universality class of the Edwards-Wilkinson equation. In particular, due to the dynamic effect of overhangs, the domain interface exhibits intrinsic anomalous scaling and spatial multiscaling behaviors, compatible with the experiments