Step-position distributions and the pairwise Einstein model for steps on crystal surfaces

Abstract

The pairwise Einstein model of steps not only justifies the use of the generalized Wigner distribution (GWD) for terrace width distributions (TWDs), it also predicts a specific form for the step position distribution (SPD), i.e., the probability density function for the fluctuations of a step about its average position. The predicted form of the SPD is well approximated by a Gaussian with a finite variance.