Spatial Ordering and Anisotropy in Surface Stress Domains and Nanostructural Evolution

Abstract

The role of elastic interaction has been well recognized for various growth modes and nanostructural self-organization on solid surfaces. Examples include spontaneous formation of stress domains in reconstructed surfaces or in phase-separating monolayers, meandering and bunching of surface steps, quantum dot formation in heteroepitaxial thin film growth, and surface roughness evolution of a stressed solid during chemical etching. The long range spatial ordering in these strain-mediated nanostructural evolution phenomena on solid surfaces is critically dependent on the anisotropy. A universal formulation is developed to examine the energetically favored orientation with respect to parameters that represent the anisotropy in elasticity and applied stress (or lattice misfit, surface stress, etc.). Nonlinear effects in surface roughness evolution are also discussed.