Step-step interactions due to anisotropic surface stress

Abstract

I have derived the effective potential that controls the motion of a single step on a crystal like Si(001) that has two inequivalent surface domains. The behavior of the steps is controlled by such a potential times a correlation length that measures the stiffness of the step edge against kinking. This correlation length may be of order 100 lattice constants. The potential derived here is compared with published images, by measuring the amplitude of thermal fluctuations in the step-edge positions.