Wandering Instability of an Isolated Step with Direct Electric Current

Abstract

We study wandering instability of an isolated step in a surface diffusion field with a direct electric currentapplied perpendicular to the step.The drift of adatoms caused by the electric currentmodifies the surface diffusion length.In sublimation the difference between the modified surface diffusion length in the upper terrace and that in the lowerterrace causes an instability with respect to fluctuation along the step.This instability occurs when the drift is opposite to thestep motion and its strength is within a limited range.Near the lower critical current the step obeys theKuramoto-Sivashinsky equation, which gives rise to spatiotemporal chaos.