Experimental advances in helium atom scattering spectroscopy over the last forty years have allowed the measurement of surface phonon dispersion curves of more than 200 different crystal surfaces and overlayers of insulators, semiconductors and metals. The first part of the book presents, at a tutorial level, the fundamental concepts and methods in surface lattice dynamics, and the theory of atom-surface interaction and inelastic scattering in their various approximations, up to the recent electron-phonon theory of helium atom scattering from conducting surfaces. The second part of the book, after introducing the experimentalist to He-atom spectrometers and the rich phenomenology of helium atom scattering from corrugated surfaces, illustrates the most significant experimental results on the surface phonon dispersion curves of various classes of insulators, semiconductors, metals, layered crystals, topological insulators, complex surfaces, adsorbates, ultra-thin films and clusters. The great potential of helium atom scattering for the study of atomic scale diffusion, THz surface collective excitations, including acoustic surface plasmons, and the future prospects of helium atom scattering are presented in the concluding chapters. The book will be valuable reading for all researchers and graduate students interested in dynamical processes at surfaces.

The systematic study of defects in semiconductors began in the early fifties. FrQm that time on many questions about the defect structure and properties have been an swered, but many others are still a matter of investigation and discussion. Moreover, during these years new problems arose in connection with the identification and char acterization of defects, their role in determining transport and optical properties of semiconductor materials and devices, as well as from the technology of the ever in creasing scale of integration. This book presents to the reader a view into both basic concepts of defect physics and recent developments of high resolution experimental techniques. The book does not aim at an exhaustive presentation of modern defect physics; rather it gathers a number of topics which represent the present-time research in this field. The volume collects the contributions to the Advanced Research Workshop "Point, Extended and Surface Defects in Semiconductors" held at the Ettore Majo rana Centre at Erice (Italy) from 2 to 7 November 1988, in the framework of the International School of Materials Science and Technology. The workshop has brought together scientists from thirteen countries. Most participants are currently working on defect problems in either silicon submicron technology or in quantum wells and superlattices, where point defects, dislocations, interfaces and surfaces are closely packed together."

In recent decades surface science has experienced a large growth in connection with the development of various experimental techniques which are able to characterize solid surfaces through the observation of the scattering of ions, electrons, photons or atoms. These methods of investigation, known under different labels such as LEED, AES, XPS, UPS, etc. have been extensively applied in describing the structure, morphology, and chemical and physical properties of crystal surfaces and interfaces of a large variety of materials of interest in solid-state physics, electronics, metallurgy, biophysics, and heterogeneous catalysis. Among these methods we wish to emphasize molecular beam scattering from solid surfaces. ~lolecular beam scattering has gone through a large development in the last ten years. In this decade a large number of laboratories have used this method to study various clean and adsorbate-covered surfaces. The technique is nonetheless quite old. It dates back to the beginning of the thirties, when Estermann and Stern performed the first atom diffraction experiment proving the wave nature of atoms. In the following years the entire subject of gas-surface interaction was considered a branch of rarefied gas dynamics and developed in connection with aerospace research. Attention was then given to the integral properties of gas-solid interactions (sticking and energy accomodation, mean momentum transfer) rather than to atom-surface scatter ing from well-characterized surfaces.

Layered crystals, characterized by a quasi-two-dimensional character of certain physical properties, play an interesting role in surface science. First of all they provide excellent inert substrates for epitaxial deposition and physisorption studies. The surfaces of layered crystals, however, are interesting in their own right because they make a relevant class of low-dimensional phenomena accessible to surface probes. Change density waves, incommensurate structures, phonon anomalies and high Tc superconductivity are well known examples. This book collects a series of review articles written by outstanding specialists on the structural assessment and spectroscopy of layered structures with surface-sensitive probes such as scanning microscopy and helium atom scattering, the theoretical analysis of their electronic and vibrational surface states, and the investigation of physisorbed overlayers.

Structural and dynamical properties of surfaces are of considerable importance for the elucidation of surface phenomena. For example, the adsorption of particles and chemical reactions at surfaces are influenced by these properties. Also, the electronic surface states of electronic device materials (e.g., Schottky barrier diodes and metal-insulator-semiconductor devices) depend critically on the structure of the semiconductor surface and the overlayers. As in "Structure and Dynamics of Surfaces I," this Topics volume considers the problems at the mircoscopic level. It deals with ordered and disordered as well as harmonic and anharmonic surface effects. Novel experimental techniques and theoretical developments which have been applied successfully during the last decade are integrated. The contributions of this volume also include the background of the subject, typical results, and, in most cases, trends of future developments.

In recent years substantial progress has been made in the detection of surface phonons owing to considerable improvements in inelastic rare gas scattering tech niques and electron energy loss spectroscopy. With these methods it has become possible to measure surface vibrations in a wide energy range for all wave vectors in the two-dimensional Brillouin zone and thus to deduce the complete surface phonon dispersion curves. Inelastic atomic beam scattering and electron energy loss spectroscopy have started to play a role in the study of surface phonons similar to the one played by inelastic neutron scattering in the investigation of bulk phonons in the last thirty years. Detailed comparison between experimen tal results and theoretical studies of inelastic surface scattering and of surface phonons has now become feasible. It is therefore possible to test and to improve the details of interaction models which have been worked out theoretically in the last few decades. At this point we felt that a concise, coherent and self-contained guide to the rapidly growing field of surface phonons was needed."

"Exotic Atoms in Condensed Matter" reviews the state of the art in this field, from meson factories to the basic interactions of muons in condensed matter. The application of muon- and pion-based analysis of solid state structural, magnetic and superconducting properties is discussed. The spectroscopic features of exotic atoms are reviewed together with their application to chemical analysis. Also, muon-catalyzed fusion is presented.

The investigation of the properties of nonlinear systems is one of the fast deve loping areas of physics. In condensed matter physics this 'terra incognita' is approached from various starting points such as phase transitions and renormali zation group theory, nonlinear models, statistical mechanics and others. The study of the mutual interrelations of these disciplines is important in developing uni fying methods and models towards a better understanding of nonlinear systems. The present book collects the lectures and seminars delivered at the workshop on "Statics and Dynamics of Nonlinear Systems" held at the Centre for SCientific Culture "Ettore Majorana." in Erice;. Italy, July 1 to 11, 1983, in the framework of the International School of Materials Science and Technology. Experts and young researchers came together to discuss nonlinear phenomena in condensed matter physics. The book is divided into five parts, each part containing a few general artic les introducing the subject, followed by related specialized papers. The first part deals with basic properties of nonlinear systems including an introduction to the general theoretical methods. Contrfbutions to the nonlinear aspects of phase transitions are collected in the second part. In the third part properties of incommensurate systems are discussed. Here, competing interactions lead to charge-density waves, soliton lattices and other complex structures. Another point of special interest, illustrated in the fourth part, is the 'chaotic' be havior of various systems such as Josephson junctions and discrete lattices."

Microcrystals large enough to be seen in an electron microscope have long been objects of intense scientific and technological interest. Recently, it has become possible to study properties of even smaller units of matter, clusters, thus allowing the last gap betweeen molecules and crystals to be bridged. This book presents the experimental and theoretical techniques needed to study this new state of condensed matter. The material is presented so as to be understandable to an audience with varied backgrounds and interests. At the beginning of each part basic concepts are quickly reviewed for graduate students and for experts who wish to broaden their interest in theory and experiments. The concepts are then applied to current problems of general interest. The basic subjects covered by the book are cluster sources, the evolution of electronic properties of condensed matter, the microscopic view of crystal growth, the chemical reactivity of clusters, cluster stability and fragmentation.

High resolution helium atom scattering can be applied to study a number of interesting properties of solid surfaces with great sensitivity and accuracy. This book treats in detail experimental and theoretical aspects ofthis method as well as all current applications in surface science. The individual chapters - all written by experts in the field - are devoted to the investigation of surface structure, defect shapes and concentrations, the interaction potential, collective and localized surface vibrations at low energies, phase transitions and surface diffusion. Over the past decade helium atom scattering has gained widespread recognitionwithin the surface science community. Points in its favour are comprehensiveunderstanding of the scattering theory and the availability of well-tested approximation to the rigorous theory. This book will be invaluable to surface scientists wishing to make an informed judgement on the actual and potential capabilities of this technique and its results.

Materials scientists are currently facing the challenge of synthesising carbon nanostructures that can reproduce or even improve on the remarkable performance of fullerenes and nanotubes, but in a robust, three-dimensional structure. Recent advances in the assembling of clusters, manipulation and functionalisation, and the extension from pure graphite-like and diamond-like materials to mixed sp2/sp3 carbon-based materials with a controlled nanostructure are leading to an impressive array of advanced applications. This volume is an up-to-date account of progress in these areas, special attention being paid to the synthesis, structural and physical characterisation, theoretical simulation and technological applications of nanostructured carbon in its innumerable forms. Readership: Graduate students, academic and industrial researchers in the field of nanophysics and related technologies.

Materials scientists are currently facing the challenge of synthesising carbon nanostructures that can reproduce or even improve on the remarkable performance of fullerenes and nanotubes, but in a robust, three-dimensional structure. Recent advances in the assembling of clusters, manipulation and functionalisation, and the extension from pure graphite-like and diamond-like materials to mixed sp2/sp3 carbon-based materials with a controlled nanostructure are leading to an impressive array of advanced applications. This volume is an up-to-date account of progress in these areas, special attention being paid to the synthesis, structural and physical characterisation, theoretical simulation and technological applications of nanostructured carbon in its innumerable forms. Readership: Graduate students, academic and industrial researchers in the field of nanophysics and related technologies.

Layered crystals, characterized by a quasi-two-dimensional character of certain physical properties, play an interesting role in surface science. First of all they provide excellent inert substrates for epitaxial deposition and physisorption studies. The surfaces of layered crystals, however, are interesting in their own right because they make a relevant class of low-dimensional phenomena accessible to surface probes. Change density waves, incommensurate structures, phonon anomalies and high Tc superconductivity are well known examples. This book collects a series of review articles written by outstanding specialists on the structural assessment and spectroscopy of layered structures with surface-sensitive probes such as scanning microscopy and helium atom scattering, the theoretical analysis of their electronic and vibrational surface states, and the investigation of physisorbed overlayers.

High resolution helium atom scattering can be applied to study a number of interesting properties of solid surfaces with great sensitivity and accuracy. This book treats in detail experimental and theoretical aspects ofthis method as well as all current applications in surface science. The individual chapters - all written by experts in the field - are devoted to the investigation of surface structure, defect shapes and concentrations, the interaction potential, collective and localized surface vibrations at low energies, phase transitions and surface diffusion. Over the past decade helium atom scattering has gained widespread recognitionwithin the surface science community. Points in its favour are comprehensiveunderstanding of the scattering theory and the availability of well-tested approximation to the rigorous theory. This book will be invaluable to surface scientists wishing to make an informed judgement on the actual and potential capabilities of this technique and its results.