Diffusive and subdiffusive step dynamics

TL;DR

This paper investigates the dynamics of steps on crystal surfaces, revealing subdiffusive behavior influenced by microscopic mechanisms, and compares different models through Langevin and Monte Carlo methods.

Contribution

It provides a comparative analysis of step dynamics under various microscopic mechanisms using Langevin equations and Monte Carlo simulations.

Findings

Step meandering exhibits subdiffusive behavior.

Asymptotic laws depend on detachment and attachment mechanisms.

Different limiting cases show distinct dynamic regimes.

Abstract

The dynamics of steps on crystal surfaces is considered. In general, the meandering of the steps obeys a subdiffusive behaviour. The characteristic asymptotic time laws depend on the microscopic mechanism for detachment and attachment of the atoms at the steps. The three limiting cases of step-edge diffusion, evaporation-condensation and terrace diffusion are studied in the framework of Langevin descriptions and by Monte Carlo simulations.