Position distribution of steps on vicinal surface and surface stiffness

As a quantity characterizing the fluctuation of steps on vicinal surface, w e study the step-position distribution function. This function gives the di stribution of the position deviation of a step from the position equidistan t from the two neighboring steps. On the basis of the harmonically-interact ing step picture for vicinal surface, the relation between the step-positio n distribution function and the surface stiffness is obtained. The relation is verified by a Monte Carlo simulation for the free-Fermion terrace-step- kink (TSK) model and the solid-on-solid step TSK model. (C) 2001 Elsevier S cience B.V. All rights reserved.