This book presents an account of the course "Disordered Solids: Structures and Processes" held in Erice, Italy, from June 15 to 29, 1987. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the "Ettore Majorana" Centre for Scientific Culture. The objective of this course was to present the advances in physical modelling, mathematical formalism and experimental techniques relevant to the interpretation of the structures of disordered solids and of the physical processes occurring therein. Traditional solid-state physics treats solids as perfect crystals and takes great advantage of their symmetry, by means of such mathematical formalisms as the reciprocal lattice, the Brillouin zone, and the powerful tools of group theory. Even if in reality no solid is a perfect crystal, this theoretical approach has been of great usefulness in describing solids: deviations from perfect order have been treated as perturbations of the ideal model. A new situation arises with truly disordered solids where any vestige of long range order has disappeared. The basic problem is that of describing these systems and gaining a scientific understanding of their physical properties without the mathematical formalism of traditional solid state physics. While some of the old approaches may occasionally remain valid (e. g. chemical bonding approach for amorphous solids), the old ways will not do. Disorder is not a perturbation: with disorder, something basically new may be expected to appear.

Structurally disordered solids are characterized by their lack of spatial order that is evidenced by the great variety of ordered solids. The former class of materials is commonly termed amorphous or glassy, the latter crystalline. However, both classes share, many of the other physical properties of solids, e. g. , me chanical stability, resistance to shear stress, etc. The traditional macroscopic distinction between the crystalline and the glassy states is that while the former has a fixed melting point, the latter does not. However, with the availability and production of a large number of materials in both crystalline and amorphous states, and their easy inter-convertability, simple de finitions are not possible or at best imprecise. For the present purpose, it is sufficient to say that in contrast to the crystalline state, in which the posi tions of atoms are fixed into adefinite structure, ex cept for small thermal vibrations, the amorphous state of the same material displays varying degrees of de parture from this fixed structure. The amorphous state almost always shows no long range order. Short range order, up to several neighbors, may often be retained, although averaged considerably around their crystalline values. It is generally believed that the amorphous state is a metastable one with respect to the crystal line ordered state, and the conversion to the crystal line state may or may not be easy depending on the na ture of the material, e. g.

This book presents a consistent mathematical theory of the non-electronic physical properties of disordered and amorphous solids, starting from the atomic-level dynamics and leading to experimentally verifiable descriptions of macroscopic properties such as elastic and viscoelastic moduli, plasticity, phonons and vibrational spectra, and thermal properties. This theory begins with the assumption of the undeniable existence of an “amorphous lattice”, which allows one to relegate the theoretical uncertainties about the ultimate nature of the glass transition to a subsidiary role and thus take a more pragmatic approach towards the modelling of physical properties. The book introduces the reader not only to the subtle physical concepts underlying the dynamics, mechanics, and statistical physics of glasses and amorphous solids, but also to the essential mathematical and numerical methods that cannot be readily gleaned from specialized literature since they are spread out among many often technically demanding papers. These methods are presented in this book in such a way as to be sufficiently general, allowing for the mathematical or numerical description of novel physical phenomena observed in many different types of amorphous solids (including soft and granular systems), regardless of the atomistic details and particular chemistry of the material. This monograph is aimed at researchers and graduate-level students in physics, materials science, physical chemistry and engineering working in the areas of amorphous materials, soft matter and granular systems, statistical physics, continuum mechanics, plasticity, and solid mechanics. It is also particularly well suited to those working on molecular dynamics simulations, molecular coarse-grained simulations, as well as ab initio atomistic and DFT methods for solid-state and materials science.

This self-contained textbook aims to introduce the physics of structurally disordered condensed systems at the level of advanced undergraduate and graduate students. The topics discussed include the geometry and symmetries of the building blocks commonly used to obtain atomic structures, the various kinds of disorder, the phenomenology and the main theories of the glass transition, investigation of the structure of amorphous systems, the dependence of system structure on its dimensions (clusters), and the case of positional order in the absence of translational order (quasicrystals).

The field of charge conduction in disordered materials is a rapidly evolving area owing to current and potential applications of these materials in various electronic devices This text aims to cover conduction in disordered solids from fundamental physical principles and theories, through practical material development with an emphasis on applications in all areas of electronic materials. International group of contributors Presents basic physical concepts developed in this field in recent years in a uniform manner Brings up-to-date, in a one-stop source, a key evolving area in the field of electronic materials

This book gives a pedagogical introduction to the physics of amorphous solids and related disordered condensed matter systems. Important concepts from statistical mechanics such as percolation, random walks, fractals and spin glasses are explained. Using these concepts, the common aspects of these systems are emphasized, and the current understanding of the glass transition and the structure of glasses are concisely reviewed. This second edition includes new material on emerging topics in the field of disordered systems such as gels, driven systems, dynamical heterogeneities, growing length scales etc. as well as an update of the literature in this rapidly developing field.