Energetics and strain field of surface steps

Stability and surface morphology of a thin film deposited in ultrahigh vacuum condition depend on strain energy stored in the thin film. Predicting the stability and morphology of such surfaces is essential for understanding, e.g., (i) the formation and growth of nanocrystals (quantum dots) in semiconductor heteroepitaxial thin film deposition and (ii) the requirements to grow flat thin films despite the presence of surface steps. This work describes a novel, theoretical model that gives rise to modified mechanical force equilibrium equations and provides a new framework to model step energetics and dynamics in heteroepitaxial thin films. Specializing in two-dimensional thin films, strain fields and energetics of a solitary surface step will be presented.