The Crystalline Solid as a Stack of Atomic Layers with Two-Dimensional Periodicity

Abstract

We have already established that for a complete analysis of the experimental data relating to electron emission one must go beyond the free-electron model of Sommerfeld. Our knowledge of the electronic properties of metals and other crystalline solids has advanced considerably during the last 20 years and a lot is presently known about the electronic energy levels and the nature of the electronic wave functions in an extended crystalline solid. During the last ten years considerable progress has also been made in our understanding of the electronic properties of solid surfaces, and, in many cases, quantitative agreement between theory and various experimental measurements has been achieved (see, e.g., Woodruff, 1981; Inglesfield and Holland, 1981). In this and the following chapter we introduce the basic concepts and some important results from the theory of the electronic properties of crystalline solids and their surfaces which are necessary for a systematic analysis of electron emission phenomena.