Siegmar Roth – författare

There is a growing interest in the connection of a single molecule or a wire of atomic diameter between two electrodes. This has led to the investigation of a class of nanoscale materials: lines of metal atoms of atom-sized cross section, lines of atomic defects, and conjugated oligomers. Several ways to fabricate such materials are discussed, such as the self assembly of metal atoms on a surface under UHV, deposition from, or sliding with an STM tip apex, and local surface modification using a voltage pulse. The synthesis of molecular wires is also presented, the objective being to produce long, low-gap, rigid conjugated oligomers. The electrical connection of a single atomic or a single molecule is more challenging: mechanical (break junction) STM or nanolithographic coplanar junctions are currently being used to measure the resistance of a single nanometer-scale wire. The theoretical problems associated with such measurements involve both solid state physics and quantum chemistry.

This volume provides a record of the second ASI on the subject "Chemical Physics of Intercalation", which was patterned after its highly successful July 1987 predecessor. A growing community of chemists, physicists and materials scientists has come to appreciate the utility of extending the intercalation concept to generic guest-host compounds and solid solutions. The unifying themes are the complex phase equilibria which result from the competition between repulsive and attractive interactions between and within the guest and host substructures, the tunability of properties by control of guest concentration and superlattice periodicity, and the broad spectrum of potential applications which these materials may provide. The success of this initiative may be judged by noting the enlarged scope of materials covered in this volume as compared to its predecessor. The present volume covers the spectrum from 3-dimensional oxides, 2-dimensional classical layer intercalates,- dimensional doped polymers and zero-dimensional doped fullerene lattices. Hybrid systems such as polymers in layer hosts and nonporous hosts are also treated. Several chapters provide global unifying viewpoints by focussing on sold state chemical aspects, transport and optical properties, the occurrence of superconductivity, etc.

An essential guide to solid state physics through the lens of dimensionality and symmetry Foundations of Solid State Physics introduces the essential topics of solid state physics as taught globally with a focus on understanding the properties of solids from the viewpoint of dimensionality and symmetry. Written in a conversational manner and designed to be accessible, the book contains a minimal amount of mathematics. The authors?noted experts on the topic?offer an insightful review of the basic topics, such as the static and dynamic lattice in real space, the reciprocal lattice, electrons in solids, and transport in materials and devices. The book also includes more advanced topics: the quasi-particle concept (phonons, solitons, polarons, excitons), strong electron-electron correlation, light-matter interactions, and spin systems. The authors' approach makes it possible to gain a clear understanding of conducting polymers, carbon nanotubes, nanowires, two-dimensional chalcogenides, perovskites and organic crystals in terms of their expressed dimension, topological connectedness, and quantum confinement. This important guide: -Offers an understanding of a variety of technology-relevant solid-state materials in terms of their dimension, topology and quantum confinement -Contains end-of-chapter problems with different degrees of difficulty to enhance understanding -Treats all classical topics of solid state physics courses - plus the physics of low-dimensional systems Written for students in physics, material sciences, and chemistry, lecturers, and other academics, Foundations of Solid State Physics explores the basic and advanced topics of solid state physics with a unique focus on dimensionality and symmetry.

At the International Winter School on "Electronic Properties of Polymers and Related Compounds" particular attention was paid to a very new and special field in polymer research. It is concerned with the study of the electronic structure of polymers and with physical and chemical properties directly re­ lated to this structure. In particular, tutorial and research contributions on electrical, electrochemical, optical, magnetic, lattice dynamical and structural properties were presented. In addition, review reports on related topics such as charge transfer complexes and linear-chain compounds (transi­ tion-metal trichalcogenides) were included. In two discussion meEjtings, the special role of polyacetylene and possible present and future applications of the electronic properties of polymers, as e.g. conductors or as electrodes in electrochemical cells, were elucidated. The electronic properties of polymers cover a wide range of research problems which are of particular interest for polymers with a 1T-electron system. Thus, a great part of the work presented was concerned with conjuga­ ted systems. Additional presentations dealt with other systems such as bio­ polymers, photopolymers or electrets, which are of significant scientific and technical importance. It was demonstrated how their electronic proper­ ties are increasingly being investigated from a fundamental point of view by applying known concepts of snlid-state science.

The International Winter School on Electronic Properties of Conjugated Polymers held March 14-21,1987, in Kirchberg (Austria) was a sequel to a meeting held in Kirchberg two years before on a similar subject. The 1987 winter school was organized in cooperation with the "Bundesministerium fiir Wissenschaft und Forschung" in Austria and the "Bundesministerium fiir Forschung und Technologie" in the Federal Republic of Germany. The basic idea of the meeting was to provide an opportunity for experienced scientists from universities and industry to discuss their most recent re- sults and for students and young scientists to inform themselves about the present state of the research in this field. As in 1985, the scientific interest was concentrated on the electronic structure of various conjugated polymers and related compounds. The focus of interest in the field now appears to have broadened and cov- ers not only conductivity and relaxation phenomena of polyacetylene but also nonlinear optical properties, highly oriented and single-crystal poly- mers, and electrochemical and opto-electrochemical properties of special materials such as polypyrrole and polyaniline.Exciting results on conduc- tivity - the mass specific conductivity (i.e., the conductivity divided by the density) of polyacetylene is more than twice that of copper (!) - and a detailed interpretation of the meaning of conjugation length are reported.

The International Winter School on Electronic Properties of Polymers and Re- lated Compounds, held March 11-18, 1989, in Kirchberg (Austria), was a sequel to two meetings on similar subjects held there two and four years be- fore. The 1989 winter school was again organized in cooperation with the "Bundesministerium flir Wissenschaft und Forschung" in Austria, and with the "Bundesministerium fUr Forschung und Technologie" in the Federal Republic of Germany. The basic idea of the meeting was to provide an opportunity for experienced scientists from universities and industry to discuss their most recent results and for students and young scientists to become familiar with the present status of research and applications in the field. Like the previous winter schools, this one concentrated on the electronic structure and application potentialities of polymers. A purely tutorial contribu- tion on high-temperature supercondutors was included. Special attention was paid this time to our present theoretical understanding of the electronic struc- ture of polymers in general, the role of disorder and the nature of the doping process in particular.Accordingly, two discussion meetings were held on the stability of quasiparticles in conjugated polymers and on the thermochromic phase transition in alkylated thiophenes. As a general result, disorder and con- jugation length were recognized as fundamental properties, not only for the stability of the quasiparticles but also for linear and nonlinear optics, transport, phototransport, magnetic properties, lattice dynamics, etc.

The International Winter School on Electronic Properties of Polymers Orien­ tation and Dimensionality of Conjugated Systems, held March 9-16, 1991, in Kirchberg, ('lYrol) Austria, was a sequel to three meetings on similar subjects held there. The 1991 winter school was again organized in cooperation with the "Bundesministerium fUr Wissenschaft und Forschung" in Austria, and with the "Bundesministerium fUr Forschung und Technologie" in the Federal Republic of Germany. The basic idea of the meeting was to provide an opportunity for experienced scientists from universities and industry to discuss their most re­ cent results and for students and young scientists to become familiar with the present status of research and applications in the field. Like the previous winter schools on polymers, this one concentrated on the electronic structure and potential~ for application of polymers with conjugated double bonds. This time, however, special attention was paid to the effects of orientation and dimensionality. Anisotropy of the electric conductivity in stretch-oriented samples and whether the transport mechanisms are one-, two-, or three-dimensional or might even have a "fractal dimensionality" were there­ fore central topics. The problem of orientation was extended to systems such as Langmuir-Blodgett films and other layered structures. Accordingly, thin films were the focus of most of the application oriented contributions. Whereas in the previous winter schools discussions on applications dealt with "large volume applications" such as electromagnetic shielding and energy storage, this time "molecular materials for electronics" and prospects of "molecular electronics" were at the center of interest.

Electronic Properties of Fullerenes and other NovelMaterials gives an overview of the state-of-the-artresearch. It presents most recent results on preparation,experimental analysis by electron spectroscopy, infrared andRaman spectroscopy, luminescence, and nonlinear optical, aswell as possible technological applications. Emphasis isalso placed on the superconducting properties of Fullerenes.The introductory and advanced contributions provide a goodsurvey of the current status of this rapidly developingfield.

This volume contains the proceedings of the NATO Advanced Research Workshop on "Atomic and Molecular Wires". It was sponsored by the Ministry of Scientific Affairs Division special program on Nanoscale Science with the support of the CNRS and the Max Planck Institute. Scientists working or interested in the properties of wires at a subnanoscale were brought together in Les Houches (France) from 6 to 10 May 1996. Subnanoscale wires can be fabricated either by surface physicists (atomic wires) or by synthetic chemists (molecular wires). Both communities present their foremost advances using, for example, STM to assemble atomic lines atom for atom, to fabricate a mask for such a line or using the wide range of chemical synthesis techniques to obtain long, rigid and conjugated oligomers. Interconnecting such tiny wires to sources (voltage, current) continues to demand a great technological effort. But nanolithography associated with microfabrication or STM are now clearly identified paths for measuring the electrical resistance of an atomic or a molecular wire. The first measurements have been reported on Xe , benzene, C ' di(phenylene-ethynylene) showing 2 60 the need for a deeper understanding of transport phenomena through subnanowires. Such transport phenomena like tunnel (off-resonance) transport and Coulomb blockade have been discussed by theorists with an emphasis on the exponential decrease of the tunnel current with the wire length versus the ballistic regime of transport.

The proceedings summarise the oral and poster presentations of the Winterschool on the above topic. The event was the sixth in a series aimed at describing and discussing recent advances in the understanding of the electronic properties of novel materials. The topic of the meeting, fullerenes and related materials, was chosen as a sequel to that of the previous year in an effort to keep abreast of this new and rapidly evolving field of research. For the duration of the week, world experts from the fields of physics, chemistry and materials science were gathered together to present their current research as well as to participate in the many lively discussions which evolved from the presentations. As such, the proceedings constitute a definitive description of the state of the art of fullerene research.

The year 1995 witnessed the tenth anniversary of the International Winterschools in Kirchberg, Tyrol/Austria. These schools are devoted to the Electronic Properties of Novel Materials, having started with coverage of research on conducting polymers and high temperature superconductors to presently focusing on Fullerene, the newly discovered third allotrope of carbon.This year's proceedings present about ten tutorial and review papers on physics, chemistry, and material science of Fullerene, Fullerene derivatives and nanotubes, as well as bout a hundred research contributions on the latest development in this field including a summary on the assessment of the applications potential of the materials and phenomena which have already evolved from the activities in the past couple of years.

During the last ten years, the International Winterschools on Electronic Properties of New Materials (IWEPNM) have developed into a well-established institution and the alumni form a very active interdisciplinary community which spreads all over the world. Past schools of this series have treated such topics as conducting polymers and high temperature superconductors. The present volume contains the proceedings of the fourth school on fullerenes and fullerene derivatives. Soccer-ball molecules, like C₆₀, C₇₀, etc., have been discovered in the late 1980's and are now regarded as the third allotrope of carbon (in addition to the classic allotropes graphite and diamond). By now, more than ten thousand original papers on fullerene have been published, and the present proceedings give a snap-shot of the development of the field and the state of the art, as reflected by research papers, overviews, and tutorial lectures. Highlights are contributions on fullerene polymers, magnetic properties of fullerene complexes, endohedral compounds, fullerenes with incorporated heteroatoms, and on fullerene nanotubes (single-walled, multi-walled, with open cores or metal-filled), as well as prospects of technological applications (field emission electron guns for flat video displays, fullerene plasma for vapour deposited diamond and SiC film, etc.).