Fluctuations of isolated and confined surface steps of monoatomic height

TL;DR

This paper investigates the equilibrium fluctuations of monoatomic height surface steps using Monte Carlo simulations, analyzing effects of diffusion, evaporation, and confinement, and compares results with theoretical predictions.

Contribution

It provides a detailed analysis of fluctuation dynamics for surface steps, including the influence of temperature, slope, curvature, and confinement, with emphasis on periphery-diffusion effects.

Findings

Fluctuation exponents depend on temperature, slope, and curvature.

Entropic repulsion can cause transient power-law growth of fluctuations.

Results align with scaling arguments and Langevin theory.

Abstract

The temporal evolution of equilibrium fluctuations for surface steps of monoatomic height is analyzed studying one-dimensional solid-on-solid models. Using Monte Carlo simulations, fluctuations due to periphery-diffusion (PD) as well as due to evaporation-condensation (EC) are considered, both for isolated steps and steps confined by the presence of straight steps. For isolated steps, the dependence of the characteristic power-laws, their exponents and prefactors, on temperature, slope, and curvature is elucidated, with the main emphasis on PD, taking into account finite-size effects. The entropic repulsion due to a second straight step may lead, among others, to an interesting transient power-law like growth of the fluctuations, for PD. Findings are compared to results of previous Monte Carlo simulations and predictions based, mostly, on scaling arguments and Langevin theory.