Asymmetry of anticrossing between atomic steps on metal and semiconductor surfaces

Abstract

The interaction between intersecting vicinal and dislocation-induced atomic steps on crystal surfaces is studied experimentally on Au(111) and GaAs(001) and numerically using Monte-Carlo simulation. The interaction between intersecting steps leads to the “anticrossing” phenomenon which consists in the formation of a three-level relief configuration with the upper and lower terraces separated by a nanometer-sized bridge of intermediate height. The anticrossing effect is driven by the effective repulsion of two new combinatory steps bordering the upper and lower terraces. Two types of asymmetry between the combinatory steps are considered. In particular, the reasons for different curvature radii of the upper and lower combinatory steps are discussed, along with the issue of why dislocation-induced steps remain straight under annealing, while vicinal steps obtain clear visible ledges.