We began planning and writing this book in thc late 1970$ at thc ugge s stion of Manuel Cardona and Helmut Latsch. We also received considerable eo­ couragement and stimulation from colleagues. Same said there was a need for instructional material in tbis area while others emphasized thc utility of a research text. We tried to strike a compromise. Thc figures, tables, and rcferences are included to enable researchcrs to obt81o quickly essential information in this area of semiconductor research. For instructoTS and stu­ dents, we attempt to cover same basic ideas abaut electronic structure and semiconductor physics with applications to real, rather than model, solids. ~Ve \Vish to thank our colleagues and collaborators whose research rc­ sults and ideas are presented here. Special thanks are duc to Jim Phillips who illfluellced lIS hoth during ollr formative )'ears and afterwards. We are grateful to Sari Yamagishi for her patience and skill with the typing and production of the manuscript. Finally, we acknowledge the great patience of Helmut Lotsch and Manucl Cardona. llerkeley, CA M.L. Gehen ~·[inncapolis, MN, J.R, Chelikew"ky March 1988 VII Contents 1. Introduction 1 2. Theoretical Concepts and Methods .................... . 4 2.1 Thc One-Electron Model and Band Structure 7 2.2 Properties cf En(k) ......................... . 11 3. Pseudopotentials 16 3.1 The Empirical Pseudopotential Method .......... 20 3.2 Self-Consistent and Ab Initio Pseudopotentials ...... ..... 25 4. Response Functiolls and Density of States . ..