Experimental Persistence Probability for Fluctuating Steps

TL;DR

This study investigates the persistence probability of fluctuating steps on a silicon surface at high temperatures, finding power-law decay consistent with theoretical predictions and supporting the attachment/detachment limited kinetics model.

Contribution

It provides experimental measurements of persistence probability for fluctuating steps and confirms theoretical predictions through numerical Langevin equation simulations.

Findings

Persistence probability follows a power law with exponent ~0.77

Experimental results align with the 3/4 theoretical prediction

Numerical Langevin simulations support experimental observations

Abstract

The persistence behavior for fluctuating steps on the $Si(111)$ $(\sqrt3 \times \sqrt3)R30^{0} - Al$ surface was determined by analyzing time-dependent STM images for temperatures between 770 and 970K. The measured persistence probability follows a power law decay with an exponent of $\theta=0.77 \pm 0.03$. This is consistent with the value of $\theta= 3/4$ predicted for attachment/detachment limited step kinetics. If the persistence analysis is carried out in terms of return to a fixed reference position, the measured persistence probability decays exponentially. Numerical studies of the Langevin equation used to model step motion corroborate the experimental observations.