Theory of Localized Electronic States at Point Imperfections

Abstract

A review is given of the present status of the theory of s and p electrons in deep traps. The theory of the F center in LiF is reviewed in detail including recent work on ionic displacements in the vicinity of the center. This is followed by a discussion of the work of Cohen and Heine and the general justification of the point ion approximation for the interaction of a trapped electron with a matrix composed of closed-shell ions. Vacancies in diamond are discussed, and new results are reported for the three-electron configuration of a vacancy in silicon. Trapped-hole centers in the alkali halides are mentioned briefly.