Elementary Tight-Binding Theory of Schottky-Barrier and Heterojunction Band Line-Ups

Abstract

The electronic structure of a solid is ordinarily represented in terms of one-electron states, each represented by a wavenumber associated with the electron’s propagation through the lattice. The energy bands give the energy of such states as a function of their wavenumber. Each of these states may be approximated as a combination of local atom-like states, with the wavenumber determining the coefficient of each such state in the propagating electronic state. If real atomic states are used, this is called the method of Linear Combinations of Atomic Orbitals. This idea is as old as Bloch’s original paper [I]; it has generally only been considered* of qualitative significance, though very often the results of more complete and accurate calculations are described in terms of such an atomic basis. Then the parameters which determine the bands are not obtained from real atomic states, but are adjusted to accord with the more accurately calculated bands; such an approach is called Tight-Binding Theory.