Regensburg 2002 – wissenschaftliches Programm
DY 40.1: Hauptvortrag
Donnerstag, 14. März 2002, 09:30–10:00, H2
Pattern formation on stepped surfaces — •Joachim Krug — Fachbereich Physik, University of Essen
Pattern-forming instabilities on stepped crystal surfaces are generally of two kinds. In step bunching, a train of equally spaced steps breaks up into bunches of high step density and large flat terraces, while in step meandering the individual steps deform laterally, with deformations of different steps usually being in phase. In the first part of the talk recent Monte Carlo simulations of growth-induced step meandering will be described, which aim at identifying the underlying mechanism from an analysis of the dependence of the meander wavelength on deposition flux and other kinetic parameters. It will be shown that the classic Bales-Zangwill instability typically competes with an alternative instability related to barriers for edge diffusion around kinks. The second part of the talk is devoted to possible mechanisms for growth-induced step bunching. In particular, a novel impurity-induced mechanism will be presented, in which the effect of impurities on the mobility of adatoms plays a decisive role. Throughout the theoretical analysis will be illustrated by pertinent experimental observations.