Short range and long range strain fields of Bi nanoline

Abstract

The practical realisation of nanoscale devices requires the development of practical nanofabrication techniques. The Bi nanolines which self-assemble on Si(001) are promising templates for atomic scale wires, and also have a fascinating subsurface reconstruction. Elastic interactions are often responsible for the limited dimensionality of epitaxial nanoscale structures. The present work examines the elastic strain field around the Bi nanoline in terms of its interaction with other surface features. A short range tensile strain around the Bi nanoline may be identified by the effect on the electronic structure of the neighbouring dimers. A longer range elastic interaction is exhibited in a repulsive interaction between the nanoline and defects and steps. Atomic resolution variable bias scanning tunnelling microscopy (STM) and first principles electronic structure calculations have been used to elucidate these effects, and excellent agreement has been found between experimental observations and theoretical results.