Giorgio Benedek – författare

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. Charge density waves, incommensurate structures, phonon anomalies and high T 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 tunneling microscopy and helium atom scattering, the theoretical analysis of their electronic and vibrational surface states, and the investigation of physisorbed overlayers.

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.

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.

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.

"Exotic Atoms in Condensed Matter" reviews the state of theart in this field, from meson factories to the basicinteractions of muons in condensed matter. The applicationof muon- and pion-based analysis of solid statestructural, magnetic and superconducting properties isdiscussed. The spectroscopic features of exotic atoms arereviewed together with their application to chemicalanalysis. 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.

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.

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.

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.

The main objective of this workshop was to review and discuss the electronic and chemical properties of layered cuprate superconductors. These are doped antiferromagnetic (AFM) insulators, and there is the possibility of a dynamic phase separation into metallic clusters and AFM areas. A clarification on the existence and the mechanism of such a phase separation is believed to be crucial for the understanding of high-Tc superconductivity in cuprates.On the one hand, theoretical and recent experimental indications in favor of this possibility were presented, on the other hand experimental papers expressing more skeptical views were also delivered. Related work on phase separations of chemical and structural origin was also included, followed by contributions on the question; “If phase separation is present, what is the pairing mechanism in the metallic clusters?”.