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This book presents high-power terahertz applications to semiconductors and semiconductor structures. It aims to bridge the gap between optics and microwave physics. It focuses on a core topic of semiconductor physics, providing a full description of the state of art of the field. The book introduces new physical phenomena which occur in the terahertz frequency range at the transition from semi-classical physics with a classical field amplitude to the fully quantized limit with photons. It covers tunneling in high-frequency fields, nonlinear absorption of radiation and radiation heating, nonlinear optics in the classical sense, Bloch-oscillations and ponderomotive forces of the terahertz radiation on free carriers, photon drag and photogalvanic effects, and terahertz spin dependent phenomena being of importance in the field of spintronics. Background information for future work and references of current literature are given. The book also discusses various experimental aspects like the generation of high-power coherent terahertz radiation, properties of materials with respect to their application in optical components, and detection schemes of short intense terahertz pulses.

The book, which is dedicated to Prof. Leonid V. Keldysh on his 75th anniversary, is a collection of review papers written by experts in condensed matter physics such as V. M. Agranovich, B. L. Altshuler, E. Burstein, V. L. Ginzburg, K. Von Klitzing, P. B. Littlewood, M. Pepper, A. Pinczuk, L. P. Pitaevskii, E. I. Rashba, T. M. Rice, etc. This is a guide-book of modern condensed matter physics, where the most important and hot topics of the field are reviewed. Topics covered include spintronics and quantum computation, Bose-Einstein condensation of excitons and the excitonic insulator, electron-hole liquid, metal-dielectric transition, coherent optical phenomena in semiconductor nanostructures, composite fermions and the quantum Hall effect, semiconductor and organic quantum wells, microcavities and other nanostructures, disordered systems in condensed matter, many-body theory and the Keldysh diagram technique, resonant acousto-optics, and inelastic electron tunneling spectroscopy.

This book presents the physics of semiconductor nanostructures with emphasis on their electronic transport properties. At its heart are five fundamental transport phenomena: quantized conductance, tunneling transport, the Aharonov–Bohm effect, the quantum Hall effect, and the Coulomb blockade effect. The book starts out with basics of solid state and semiconductor physics, such as crystal structure, band structure, and effective mass approximation, including spin-orbit interaction effects important for research in semiconductor spintronics. It deals with material aspects such as band engineering, doping, gating, and a selection of nanostructure fabrication techniques. The book discusses the Drude–Boltzmann–Sommerfeld transport theory as well as conductance quantization and the Landauer–Büttiker theory. These concepts are extended to mesoscopic interference phenomena and decoherence, magnetotransport, and interaction effects in quantum-confined systems, guiding the reader from fundamental effects to specialized state-of-the-art experiments.

For hundreds of years, models of magnetism have been pivotal in the understanding and advancement of science and technology, from the Earth's interpretation as a magnetic dipole to quantum mechanics, statistical physics, and modern nanotechnology. This book is the first to envision the field of magnetism in its entirety. It complements a rich literature on specific models of magnetism and provides an introduction to simple models, including some simple limits of complicated models. The book is written in an easily accessible style, with a limited amount of mathematics, and covers a wide range of models on quantum mechanics, finite temperature, micromagnetics, and dynamics. It deals not only with basic magnetic quantities, such as moment, Curie temperature, anisotropy, and coercivity, but also with modern areas such as nanomagnetism and spintronics, and with ‘exotic’ themes, as exemplified by the polymer analogy of magnetic phase transitions. Throughout the book, a sharp line is drawn between simple and simplistic models, and much space is devoted to discussing the merits and failures of the individual model approaches.

The book treats in a unified way electronic properties of molecules (magnetic, electrical, photophysical), culminating with the mastering of electrons, i.e. molecular electronics and spintronics and molecular machines. Chapter 1 recalls basic concepts. Chapter 2 describes the magnetic properties due to localized electrons. This includes phenomena such as spin cross-over, exchange interaction from dihydrogen to extended molecular magnetic systems, and magnetic anisotropy with single-molecule magnets. Chapter 3 is devoted to the electrical properties due to moving electrons. One considers first electron transfer in discrete molecular systems, in particular in mixed valence compounds. Then, extended molecular solids, in particular molecular conductors, are described by band theory. Special attention is paid to structural distortions (Peierls instability) and interelectronic repulsions in narrow-band systems. Chapter 4 treats photophysical properties, mainly electron transfer in the excited state and its applications to photodiodes, organic light emitting diodes, photovoltaic cells and water photolysis. Energy transfer is also treated. Photomagnetism (how a photonic excitation modifies magnetic properties) is introduced. Finally, Chapter 5 combines the previous knowledge for three advanced subjects: first molecular electronics in its hybrid form (molecules connected to electrodes acting as wires, diodes, memory elements, field-effect transistors) or in the quantum computation approach. Then, molecular spintronics, using, besides the charge, the spin of the electron. Finally the theme of molecular machines is presented, with the problem of the directionality control of their motion.

Since the discovery of the giant magnetoresistance effect in magnetic multilayers in 1988, a new branch of physics and technology, called spin-electronics or spintronics, has emerged, where the flow of electrical charge as well as the flow of electron spin, the so-called “spin current,” are manipulated and controlled together. The physics of magnetism and the application of spin current have progressed in tandem with the nanofabrication technology of magnets and the engineering of interfaces and thin films. This book aims to provide an introduction and guide to the new physics and applications of spin current, with an emphasis on the interaction between spin and charge currents in magnetic nanostructures.

This book sets out the fundamental quantum processes that are important in the physics and technology of semiconductors in a relatively informal style. The fifth edition includes new chapters that expand the coverage of semiconductor physics relevant to its accompanying technology. One of the problems encountered in high-power transistors is the excessive production of phonons, and the first new chapter examines the hot-phonon phenomenon and the lifetime of polar optical phonons in the nitrides. In the burgeoning field of spintronics a crucial parameter is the lifetime of a spin-polarised electron gas, and this is treated in detail in the second of the new chapters. The third new chapter moves from the treatment of bulk properties to the unavoidable effects of the spatial limitation of the semiconductor, and to the influence of surface states and the pinning of the Fermi level. As with previous editions the text restricts its attention to bulk semiconductors. The account progresses from quantum processes describable by density matrices, through the semi-classical Boltzmann equation and its solutions, to the drift-diffusion description of space-charge waves, the latter appearing in the contexts of negative differential resistance, acoustoelectric and recombination instabilities.

Since the discovery of the giant magnetoresistance effect in magnetic multilayers in 1988, a new branch of physics and technology, called spin-electronics or spintronics, has emerged, where the flow of electrical charge as well as the flow of electron spin, the so-called ‘spin current’, are manipulated and controlled together. The physics of magnetism and the application of spin current have progressed in tandem with the nanofabrication technology of magnets and the engineering of interfaces and thin films. This book aims to provide an introduction and guide to the new physics and applications of spin current, with an emphasis on the interaction between spin and charge currents in magnetic nanostructures.

This book treats in a unified way electronic properties of molecules (magnetic, electrical, photophysical), culminating with the mastering of electrons: molecular electronics. Chapter 1 reviews basic concepts. Chapter 2 describes the magnetic properties due to localized electrons. This includes phenomena such as spin crossover, exchange interaction from dihydrogen to extended molecular magnetic systems, and magnetic anisotropy with single-molecule magnets. Chapter 3 is devoted to electrical properties due to moving electrons, first considering electron transfer in discrete molecular systems — in particular, in mixed valence compounds — and then, extended molecular solids described by band theory. Special attention is paid to structural distortions (Peierls instability) and interelectronic repulsions in narrow-band systems. Chapter 4 examines the properties of excited electrons responsible for photophysical properties, and dicusses electron transfer in the excited state and its application to photodiodes, organic light-emitting diodes, photovoltaic devices, and water photolysis. Energy transfer is treated in a similar way. Photomagnetism (how a photonic excitation modifies magnetic properties) is also introduced. In Chapter 5, most of the previous knowledge is combined in molecular electronics. The concept of hybrid molecular electronics (molecules connected to metal electrodes) is developed, fed by examples such as molecular wires, diodes, memory elements, field-effect transistors, and the use of magnetic properties for molecular spintronics. The extension to quantum computing is discussed.