Chapter 2: Ab-initio studies of structural and electronic properties

Ab initio calculations are an important tool for reliable and accurate predictions of structural and electronic properties of specific semiconductor heterostructures and nanostructures and are also essential for understanding the underlying mechanisms governing their most important physical properties, establishing a rationale for the peculiarities of entire classes of systems, and gaining the necessary insight to engineer their properties for specific applications. In this chapter, we present the basic ingredients of an ab initio approach to heterostructures and nanostructures and discuss their application to prototypical systems. Among the electronic properties, particular emphasis is placed on the band alignments at semiconductor-based heterojunctions, which are the key parameters governing their transport properties, but other features are also discussed, such as localized electron states at interfaces and cross-sectional scanning tunneling microscopy images. We focus mostly on ab initio computations and theoretical models derived from first-principle numerical experiments.