Nanostructure and velocity of field-driven solid-on-solid interfaces moving under a phonon-assisted dynamic

TL;DR

This study investigates the structure and velocity of driven solid-on-solid interfaces in an Ising model coupled to a phonon bath, revealing nonmonotonic behavior and transition restrictions that impact interface dynamics.

Contribution

It introduces a phonon-assisted dynamic for solid-on-solid interfaces, providing analytical and simulation insights into non-equilibrium behavior and transition effects.

Findings

Interface width varies nonmonotonically with force

Significant differences between theory and simulation near specific forces

Transitions forbidden by phonon dynamics affect interface properties

Abstract

The nanoscopic structure and the stationary propagation velocity of (1+1)-dimensional solid-on-solid interfaces in an Ising lattice-gas model, which are driven far from equilibrium by an applied force, such as a magnetic field or a difference in (electro)chemical potential, are studied by an analytic nonlinear-response approximation together with kinetic Monte Carlo simulations. Here we consider the case that the system is coupled to a two-dimensional phonon bath. In the resulting dynamic, transitions that conserve the system energy are forbidden, and the effects of the applied force and the interaction energies do not factorize (a so-called hard dynamic). In full agreement with previous general theoretical results we find that the local interface width changes dramatically with the applied force. However, in contrast with other hard dynamics, this change is nonmonotonic in the driving force. However, significant differences between theory and simulation are found near two special values of the driving force, where certain transitions allowed by the solid-on-solid model become forbidden by the phonon-assisted dynamic. Our results represent a significant step toward providing a solid physical foundation for kinetic Monte Carlo simulations.