Organic and Inorganic Low-Dimensional Crystalline Materials


Book Description

The research of unitary concepts in solid state and molecular chemistry is of current interest for both chemist and physicist communities. It is clear that due to their relative simplicity, low dimensional materials have attracted most of the attention. Thus, many non-trivial problems were solved in chain systems, giving some insight into the behavior of real systems which would otherwise be untractable. The NATO Advanced Research Workshop on "Organic and Inorganic Low-Dimensional Crystalline Materials" was organized to review the most striking electronic properties exhibited by organic and inorganic sytems whose space dimensionality ranges from zero (Od) to one (1d), and to discuss related scientific and technological potentials. The initial objectives of this Workshop were, respectively: i) To research unitary concepts in solid state physics, in particular for one dimensional compounds, ii) To reinforce, through a close coupling between theory and experiment, the interplay between organic and inorganic chemistry, on the one hand, and solid state physics on the other, iii) To get a salient understanding of new low-dimensional materials showing "exotic" physical properties, in conjunction with structural features.







Organic Conductors


Book Description

This work examines all aspects of organic conductors, detailing recent theoretical concepts and current laboratory methods of synthesis, measurement, control and analysis. It describes advances in molecular-scale engineering, including switching and memory systems, Schottky and electroluminescent diodes, field-effect transistors, and photovoltaic devices and solar cells.




Research Frontiers in Magnetochemistry


Book Description

Over the past 25 years, there have been many advances in the understanding of magnetic phenomena in molecular systems. For example, a variety of low-dimensional materials, and many new ferromagnetic, antiferromagnetic, and ferrimagnetic systems have been synthesized and analyzed; metal cluster compounds that exhibit magnetic exchange have been examined; new orbital overlap theories have been proposed to explain magneto-structural correlations in exchange coupled systems; and efforts directed toward the preparation of an organic ferromagnetic material have produced new and interesting compounds. There have also been many advances in the use of magnetism as a probe of inorganic biomolecules.This volume brings together reviews of current research in magnetochemistry that are written by the world's leading researchers in the fields of chemistry, physics, materials science, and magnetism. It contains comprehensive and in-depth reviews that describe some of the current activities of these scientists and their research and lays the foundation for future research endeavors.




Guidelines for Mastering the Properties of Molecular Sieves


Book Description

Low dimensionality is a multifarious concept which applies to very diversified materials. Thus, examples of low-dimensional systems are structures with one or several layers, single lines or patterns of lines, and small clusters isolated or dispersed in solid systems. Such low dimensional features can be produced in a wide variety of materials systems with a broad spectrum of scientific and practical interests. These features, in turn, induce specific properties and, particularly, specific transport properties. In the case of zeolites, low dimensionality appears in the network of small-diameter pores of molecular size, extending in one, two or three di mensions, that these solids exhibit as a characteristic feature and which explains the term of "molecular sieves" currently used to name these ma terials. Indeed, a large number of industrial processes for separation of gases and liquids, and for catalysis are based upon the use of this low dimensional feature in zeolites. For instance, zeolites constitute the first class of catalysts employed allover the world. Because of the peculiarity and flexibility of their structure (and composition), zeolites can be adapted to suit many specific and diversified applications. For this reason, zeolites are presently the object of a large and fast-growing interest among chemists and chemical engineers.




Low-dimensional Organic Conductors


Book Description

This book is a review of physical properties of organic conductors and superconductors. It is amply illustrated and contains numerous data concerning the latest elements and equipment constructed of low-dimensional organic conductors. It is hoped that the book will be stimulating for technologists and designers working on contemporary electronics.




Dynamics of Magnetic Fluctuations in High-Temperature Superconductors


Book Description

This NATO Advanced Research Workshop was held at a time when there was little consensus as to the mechanism for high temperature superconductivity, in the context of a world undergoing major changes in its political alignments and sense of the possibility for the future. It was characterized by generosity in the sharing of our uncertainties and speculations, as was appropriate for both the subject matter and the context. The workshop was organized, of necessity around the experimental work, as is this volume. Where the theoretical work is directly relevant to particular experiments, it is included in the appropriate sections with them. Most of the participants felt strongly that magnetic fluctuations played an important role in the mechanism for high T c, although with the exception of the IlS R work reported by Luke showing results inconsistent with the anyon picture, and the work on flux phases by Lederer, the mechanism remained an issue in the background. A major focus was the phenomenological interpretation of the NMR data.




Point and Extended Defects in Semiconductors


Book Description

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.




Light Scattering in Semiconductor Structures and Superlattices


Book Description

Just over 25 years ago the first laser-excited Raman spectrum of any crystal was obtained. In November 1964, Hobden and Russell reported the Raman spectrum of GaP and later, in June 1965, Russell published the Si spectrum. Then, in July 1965, the forerunner of a series of meetings on light scattering in solids was held in Paris. Laser Raman spectroscopy of semiconductors was at the forefront in new developments at this meeting. Similar meetings were held in 1968 (New York), 1971 (Paris) and 1975 (Campinas). Since then, and apart from the multidisciplinary biennial International Conference on Raman Spectroscopy there has been no special forum for experts in light scattering spectroscopy of semiconductors to meet and discuss latest developments. Meanwhile, technological advances in semiconductor growth have given rise to a veritable renaissance in the field of semiconductor physics. Light scattering spectroscopy has played a crucial role in the advancement of this field, providing valuable information about the electronic, vibrational and structural properties both of the host materials, and of heterogeneous composite structures. On entering a new decade, one in which technological advances in lithography promise to open even broader horirons for semiconductor physics, it seemed to us to be an ideal time to reflect on the achievements of the past decade, to be brought up to date on the current state-of-the-art, and to catch some glimpses of where the field might be headed in the 1990s.




Resonant Tunneling in Semiconductors


Book Description

This book contains the proceedings of the NATO Advanced Research Workshop on "Resonant Tunneling in Semiconductors: Physics and Applications", held at Escorial, Spain, on May 14-18, 1990. The tremendous growth in the past two decades in the field of resonant tunneling in semiconductor heterostructures has followed, if not outpaced, the expansion wit nessed in quantum structures in general. Resonant tunneling shares also the multi disciplinary nature of that broad area, with an emphasis on the underlying physics but with a coverage of material systems on the one end and device applications on the other. Indeed, that resonant tunneling provides great flexibility in terms of materials and configurations and that it is inherently a fast process with obvious device impli cations by the presence of a negative differential resistance have contributed to the unrelenting interest in this field. These proceedings consist of 49 refereed articles; they correspond to both invited and contributed talks at the workshop. Because of the intertwinning nature of the subject matter, it has been difficult to subdivide them in well-defined sections. Instead, they are arranged in several broad categories, meant to serve only as guidelines of emphasis on different topics and aspects. The book starts with an introduction to res onant tunneling by providing a perspective of the field in the first article. This is fol lowed by discussions of different material systems with various band-structure effects.