Modern Problems in Condensed Matter Sciences Series

In the twenty years since Zabusky and Kruskal coined the term ``soliton'', this concept changed the outlook on certain types of nonlinear phenomena and found its way into all branches of physics. The present volume deals with a great variety of applications of the new concept in condensed-matter physics, which is particularly reached in experimentally observable occurrences. The presentation is not centred around the mathematical aspects; the emphasis is on the physical nature of the nonlinear phenomena occurring in particular situations. With its emphasis on concrete, mostly experimentally verifiable cases, ``Solitons'' constitutes a very readable and instructive introduction to the subject as well as an up-to-date account of current developments in a field of research reaching maturity.

``Electron-Electron Interactions in Disordered Systems'' deals with the interplay of disorder and the Coulomb interaction. Prominent experts give state-of-the-art reviews of the theoretical and experimental work in this field and make it clear that the interplay of the two effects is essential, especially in low-dimensional systems.

Modern Problems in Condensed Matter Sciences, Volume I: Surface Polaritons: Electromagnetic Waves at Surfaces and Interfaces describes the basic properties of surface polaritons and the methods of generating these waves in the laboratory at frequencies of interest to condensed matter physicists. The selection first elaborates on surface phonon polaritons in dielectrics and semiconductors and surface exciton polaritons from the experimental viewpoint. Discussions focus on interface polaritons; surface vibrations in anisotropic crystals; experimental methods for the excitation and study of surface polaritons; and surface vibrations in isotropic crystals. The publication then ponders on surface electromagnetic wave propagation on metal surfaces; thermally stimulated emission of surface polaritons; and effects of the transition layer and spatial dispersion in the spectra of surface polaritons. The text takes a look at surface polaritons at metal surfaces and interfaces and resonance of transition layer excitations with surface polaritons. Topics include resonance of the film phonon with the substrate surface phonon polaritons; investigations of surface modifications in ultra-high vacuum; and use of surface plasma waves for the investigation of solid-liquid and solid-solid interfaces. The selection is a dependable reference for physicists and engineers wanting to conduct research on surface polaritons.

``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown. As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

``Physics of Radiation Effects in Crystals'' is presented in two parts. The first part covers the general background and theory of radiation effects in crystals, including the theory describing the generation of crystal lattice defects by radiation, the kinetic approach to the study of the disposition of these defects and the effects of the diffusion of these defects on alloy compositions and phases. Specific problems of current interest are treated in the second part and include anisotropic dimensional changes in x-uranium, zirconium and graphite, acceleration of thermal creep in reactor materials, and radiation damage of semiconductors and superconductors.

``Semimetals'' presents, for the first time in the literature, a consistent and unifying treatment of semimetals (As, Bi, Sb, Bi-Sb alloys, graphite and its compounds). It describes their structural features and their electric, magnetic, galvanomagnetic, thermoelectric, optical, magneto-optical, acoustic, thermal, and mechanical properties on the basis of modern concepts of the electron and phonon energy spectra. The book discusses in detail the character of the changes in the energy spectrum and properties of semimetals due to temperature variations, application of a magnetic field, pressure, anisotropic strain, doping by donor, acceptor and neutral impurities, which indicate how the above properties may be altered and how materials with preassigned parameters can be produced. Furthermore, it discusses specific phenomena associated with low dimensionality and the very low carrier density, such as quantum oscillations and magnetoplasma behaviour.

The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics. The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop. The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and an examination of the possible role of solitons in incommensurate charge density wave systems is given. A number of ways to describe charge density waves theoretically, using computer simulations as well as microscopical models, are presented by a truely international board of authors.

``Optical Properties of Mixed Crystals'' is concerned with the description of optical processes in substitutionally disordered semiconductors and insulators which can be basically described through their elementary excitations. Two of the chapters relate to the phonon response including the effect of side bands on electron transitions. Two relate to electronic spectra, one on photoelectron spectroscopy and the other on excitons. A further chapter deals with magnons in magnetic crystals and a final chapter is related to fluctuations and band edge effects. Each chapter deals with a specific class of excitation, but the book makes it clear that the fundamental structure of the excitation spectra, including band formation, band tailing and localisation is common to every type of excitation. The volume shows how some basic concepts and ideas can be widely applied to bring coherence and understanding to a diverse area of solid state physics. It therefore provides an up-to-date summary of the experimental and theoretical situation in an important and rapidly developing field and brings together for the first time a discussion of the many different types of spectra which appear in mixed crystals.

The transport properties of solids, as well as the many optical phenomena in them are determined by the scattering of current carriers. ``Carrier Scattering in Metals and Semiconductors'' elucidates the state of the art in the research on the scattering mechanisms for current carriers in metals and semiconductors and describes experiments in which these mechanisms are most dramatically manifested. The selection and organization of the material is in a form to prepare the reader to reason independently and to deal just as independently with available theoretical results and experimental data. The subjects dealt with include: - electronic transport theory based on the test-particle and correlation-function concepts; - scattering by phonons, impurities, surfaces, magnons, dislocations, electron-electron scattering and electron temperature; - two-phonon scattering, spin-flip scattering, scattering in degenerate and many-band models.

``Spectroscopy of Crystals Containing Rare Earth Ions'' contains chapters on some key problems selected from a broad range of spectroscopic studies of RE-activated solids including both crystalline and glassy materials. Progress in crystal field theory is surveyed, an area which is basic to our understanding of the energy levels. The treatment of dynamical properties includes studies of coherence phenomena in isolated ions, energy transfer between ions and co-operative phenomena associated with ion-ion and ion-lattice interactions. In addition, the role of electron spins and nuclear spins is studied by light scattering and double resonance techniques. The presence of inhomogeneous broadening of spectral lines is observed and studied in many contexts, leading to new insights into general problems of the disordered state. Considerable attention is devoted to describing new experimental techniques whose development is of prime importance for progress in the spectroscopy of RE-activated solids. Many of these rely on the development and application of tunable lasers. At the moment this is a very active field of spectroscopy with more exciting developments likely to occur in the future.

This volume aims to provide a thorough treatment of the phenomena of elastic anisostropy and a discussion on dislocation mobilities. The book presents a wide treatment of these topics, and includes descriptions of detailed theoretical models to describe dislocations and cracks, and moving dislocations. An overview is given of the physical behaviour resulting from dislocation mobility in materials, such as glide and climb, interactions with point defects and the behaviour of dislocations under radiation such as creep and swelling.

In recent years the physics of electromagnetic surface phenomena has developed rapidly, evolving into technologies for communications and industry, such as fiber and integrated optics. The variety of phenomena based on electromagnetism at surfaces is rich and this book was written with the aim of summarizing the available knowledge in selected areas of the field. The book contains reviews written by solid state and optical physicists on the nonlinear interaction of electromagnetic waves at and with surfaces and films. Both the physical phenomena and some potential applications are dealt with. Included are discussions of nonlinear wave mixing on films and surfaces, second harmonic generation in waveguides and at surfaces, nonlinear waves guided by dielectric and semiconductor surfaces and films, surface gratings formed by high energy laser beams, and reflection and transmission switching of strong beams onto nonlinear surfaces. Chapters on light scattering from surface excitations and magnetic order-disorder and orientational phase transitions complete this essential contribution to the modern optics literature.

Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle electronic structure calculations and critical phenomena - has given rise to impressive new insights. Clearly, there is more and more need for accurate, stable numerical simulations of models of interacting electrons, presently discussed with great vigor in connection with high-Tc superconductors where the superconducting transition is close to a magnetic transition, i.e. an antiferromagnetic spin structure. These topics and others are discussed and reviewed by leading experts in the field.

Introducing the subject of superfluid helium three and polarized liquid helium three, this book is devoted to modern problems in many body physics specific to the quantum fluid helium three. Relationships between properties of helium three and topics in other fields are established including superconductivity, non-linear dynamics, acoustics, and magnetically polarized quantum systems. Among the chapters in this collection one finds valuable reference material and original research not published elsewhere. Advanced research topics are presented in a pedagogical manner, in considerable depth, and with appropriate introductory material sufficiently general to be suitable to the non-specialist.

In recent years, great progress has been made in the understanding of recombination processes controlling the number of excess free carriers in semiconductors under nonequilibrium conditions. As a result, it is now possible to give a comprehensive theoretical description of these processes. The authors have selected a number of experimental results which elucidate the underlying physical problems and enable a test of theoretical models. The following topics are dealt with: phenomenological theory of recombination, theoretical models of shallow and deep localized states, cascade model of carrier capture by impurity centers, capture restricted by diffusion, multiphonon processes, Auger processes, effect of electric field on capture and thermal emission of carriers.

Much progress has been made in the understanding of the general properties of the dielectric function and in the calculation of this quantity for many classes of media. This volume gathers together the considerable information available and presents a detailed overview of the present status of the theory of electromagnetic response functions, whilst simultaneously covering a wide range of problems in its application to condensed matter physics. The following subjects are covered: - the dielectric function of the homogeneous electron gas, of crystalline systems, and of inhomogeneous matter; - electromagnetic fluctuations and molecular forces in condensed matter; - electrodynamics of superlattices.

This book comprises the first systematic exposition of various physical aspects of the orientation of electron and nuclear spins in semiconductors by optical means.

The essays in this book deal with of the problem of quantum tunnelling and related behavior of a microscopic or macroscopic system, which interacts strongly with an "environment" - this being some form of condensed matter. The "system" in question need not be physically distinct from its environment, but could, for example, be one particular degree of freedom on which attention is focussed, as in the case of the Josephson junction studied in several of the papers. This general problem has been studied in many hundreds, if not thousands, of articles in the literature, in contexts as diverse as biophysics and quantum cosmology. The editors have grouped together papers which are representative of the main trends in this area in the last fifteen years or so and sufficiently related in general spirit and terminology that common themes can be discerned. The contributions are primarily theoretical, but the comparison with experiment is discussed wherever possible.

The physics of nonequilibrium electrons and phonons in semiconductors is an important branch of fundamental physics that has many practical applications, especially in the development of ultrafast and ultrasmall semiconductor devices. This volume is devoted to different trends in the field which are presently at the forefront of research. Special attention is paid to the ultrafast relaxation processes in bulk semiconductors and two-dimensional semiconductor structures, and to their study by different spectroscopic methods, both pulsed and steady-state. The evolution of energy and space distribution of nonequilibrium electrons and the relaxation kinetics of hot carriers and phonons are considered under various conditions such as temperature, doping and pumping intensity by leading experts in the field.

The physics of disordered systems has enjoyed a resurgence of interest in the last decade. New concepts such as weak localization, interaction effects and Coulomb gap, have been developed for the transport properties of metals and insulators. With the fabrication of smaller and smaller samples and the routine availability of low temperatures, new physics has emerged from the studies of small devices. The new field goes under the name "mesoscopic physics" and has rapidly developed, both experimentally and theoretically. This book is designed to review the current status of the field. Most of the chapters in the book are devoted to the development of new ideas in the field. They include reviews of experimental observations of conductance fluctuations and the Aharonov-Bohm oscillations in disordered metals, theoretical and experimental work on low frequency noise in small disordered systems, transmittancy fluctuations through random barriers, and theoretical work on the distribution of fluctuation quantities such as conductance. Two chapters are not connected directly to the mesoscopic fluctuations but deal with small systems. They cover the effects of Coulomb interaction in the tunneling through the small junctions, and experimental results on ballistic transport through a perfect conductor.

Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals. A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.