Semiconductors and Semimetals

”Quantum Phenomena do not occur in a Hilbert space. They occur in a laboratory”. - Asher Peres Semiconductor physics is a laboratory to learn and discover the concepts of quantum mechanics and thermodynamics, condensed matter physics, and materials science, and the payoffs are almost immediate in the form of useful semiconductor devices. Debdeep Jena has had the opportunity to work on both sides of the fence - on the fundamental materials science and quantum physics of semiconductors, and in their applications in semiconductor electronic and photonic devices. In Quantum Physics of Semiconductors and Nanostructures, Jena uses this experience to make each topic as tangible and accessible as possible to students at all levels. Consider the simplest physical processes that occur in semiconductors: electron or hole transport in bands and over barriers, collision of electrons with the atoms in the crystal, or when electrons and holes annihilate each other to produce a photon. The correct explanation of these processes require a quantum mechanical treatment. Any shortcuts lead to misconceptions that can take years to dispel, and sometimes become roadblocks towards a deeper understanding and appreciation of the richness of the subject. A typical introductory course on semiconductor physics would then require prerequisites of quantum mechanics, statistical physics and thermodynamics, materials science, and electromagnetism. Rarely would a student have all this background when (s)he takes a course of this nature in most universities. Jena's work fills in these gaps and gives students the background and deeper understanding of the quantum physics of semiconductors and nanostructures.

We began planning and writing this book in the late 1970s at the suggestion of Manuel Cardona and Helmut Lotsch. We also received considerable en couragement and stimulation from colleagues. Some said there was a need for instructional material in this area while others emphasized the utility of a research text. We tried to strike a compromise. The figures, tables, and references are included to enable researchers to obtain quickly essential information in this area of semiconductor research. For instructors and stu dents, we attempt to cover some basic ideas about electronic structure and semiconductor physics with applications to real, rather than model, solids. We wish to thank our colleagues and collaborators whose research re sults and ideas are presented here. Special thanks are due to Jim Phillips who influenced us both during our formative years 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 Manuel Cardona. Berkeley, CA M.L. Cohen Minneapolis, MN, J.R. Chelikowsky March 1988 VII Contents 1. Introduction............................................... 1 2. Theoretical Concepts and Methods ..................... 4 2.1 The One-Electron Model and Band Structure............ 7 2.2 Properties of En(k) ...................................... 11 3. Pseudopotentials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 . . . . . . . . . . . . 3.1 The Empirical Pseudopotential Method.................. 20 3.2 Self-Consistent and Ab Initio Pseudopotentials ........... 25 4. Response Functions and Density of States .............. 30 4.1 Charge Density and Bonding ................... . . . . . . . . . 38 .

The Committee to Assess the Current Status and Future Direction of High Magnetic Field Science in the United States was convened by the National Research Council in response to a request by the National Science Foundation. This report answers three questions: (1) What is the current state of high-field magnet science, engineering, and technology in the United States, and are there any conspicuous needs to be addressed? (2) What are the current science drivers and which scientific opportunities and challenges can be anticipated over the next ten years? (3) What are the principal existing and planned high magnetic field facilities outside of the United States, what roles have U.S. high field magnet development efforts played in developing those facilities, and what potentials exist for further international collaboration in this area? A magnetic field is produced by an electrical current in a metal coil. This current exerts an expansive force on the coil, and a magnetic field is "high" if it challenges the strength and current-carrying capacity of the materials that create the field. Although lower magnetic fields can be achieved using commercially available magnets, research in the highest achievable fields has been, and will continue to be, most often performed in large research centers that possess the materials and systems know-how for forefront research. Only a few high field centers exist around the world; in the United States, the principal center is the National High Magnetic Field Laboratory (NHMFL). High Magnetic Field Science and Its Application in the United States considers continued support for a centralized high-field facility such as NHFML to be the highest priority. This report contains a recommendation for the funding and siting of several new high field nuclear magnetic resonance magnets at user facilities in different regions of the United States. Continued advancement in high-magnetic field science requires substantial investments in magnets with enhanced capabilities. High Magnetic Field Science and Its Application in the United States contains recommendations for the further development of all-superconducting, hybrid, and higher field pulsed magnets that meet ambitious but achievable goals.

Materials science has undergone a revolutionary transformation in the past two decades. It is an interdisciplinary field that has grown out of chemistry, physics, biology, and engineering departments. In this book, González-Viñas and Mancini provide an introduction to the field, one that emphasizes a qualitative understanding of the subject, rather than an intensely mathematical one. The book covers the topics usually treated in a first course on materials science, such as crystalline solids and defects. It describes the electrical, mechanical, and thermal properties of matter; the unique properties of dielectric and magnetic materials; the phenomenon of superconductivity; polymers; and optical and amorphous materials. More modern subjects, such as fullerenes, liquid crystals, and surface phenomena are also covered, and problems are included at the end of each chapter. An Introduction to Materials Science is addressed to both undergraduate students with basic skills in chemistry and physics, and those who simply want to know more about the topics on which the book focuses.

A self-contained and up-to-date account of the current developments in the physics and technology of nanowire semiconductor devices.

The monograph reviews various aspects of electronic properties of Dirac and Weyl semimetals. After a brief discussion of 2D Dirac semimetals, a comprehensive review of 3D materials is given. The description starts from an overview of the topological properties and symmetries of Dirac and Weyl semimetals. In addition, several low-energy models of Dirac and Weyl quasiparticles are presented. The key ab initio approaches and material realizations are given. The monograph includes detailed discussions of the surface Fermi arcs, anomalous transport properties, and collective modes of Dirac and Weyl semimetals. Superconductivity in these materials is briefly addressed.

Semiconductor Materials presents physico-chemical, electronic, electrical, elastic, mechanical, magnetic, optical, and other properties of a vast group of elemental, binary, and ternary inorganic semiconductors and their solid solutions. It also discusses the properties of organic semiconductors. Descriptions are given of the most commonly used semiconductor devices-charge-coupled devices, field-effect transistors, unijunction transistors, thyristors, Zener and avalanche diodes, and photodiodes and lasers. The current trend of transitioning from silicon technology to gallium arsenide technology in field-effect-based electronic devices is a special feature that is also covered. More than 300 figures and 100 tables highlight discussions in the text, and more than 2,000 references guide you to further sources on specific topics. Semiconductor Materials is a relatively compact book containing vast information on semiconductor material properties. Readers can compare results of the property measurements that have been reported by different authors and critically compare the data using the reference information contained in the book. Engineers who design and improve semiconductor devices, researchers in physics and chemistry, and students of materials science and electronics will find this a valuable guide.