Landau Theory Of Phase Transitions The Application To Structural Incommensurate Magnetic And Liquid Crystal Systems

The contents of this book stems from three different objectives. First, it is an introduction to the basic principles and techniques of Landau's theory, which is intended for teaching purposes. A second purpose of the book provides the practical methods for applying Landau's theory to complex systems. The last objective of the book is to incorporate the developments which have arisen in the last fifteen years from the extensive application of the theory to a variety of physical systems.

Intended for readers with some prior knowledge of condensed-matter physics, this text emphasises the basic physics behind spontaneous structural changes in crystals. Starting with the relevant thermodynamic principles, the author discusses the nature of order variables and their collective motion in a crystal lattice. He also goes on to describe experimental methods for modulated crystal structures and gives examples of structural changes in representative systems. Both a graduate text and reference work.

About half a century ago Landau formulated the central principles of the phe nomenological second-order phase transition theory which is based on the idea of spontaneous symmetry breaking at phase transition. By means of this ap proach it has been possible to treat phase transitions of different nature in altogether distinct systems from a unified viewpoint, to embrace the aforemen tioned transitions by a unified body of mathematics and to show that, in a certain sense, physical systems in the vicinity of second-order phase transitions exhibit universal behavior. For several decades the Landau method has been extensively used to an alyze specific phase transitions in systems and has been providing a basis for interpreting experimental data on the behavior of physical characteristics near the phase transition, including the behavior of these characteristics in systems subject to various external effects such as pressure, electric and magnetic fields, deformation, etc. The symmetry aspects of Landau's theory are perhaps most effective in analyzing phase transitions in crystals because the relevant body of mathemat ics for this symmetry, namely, the crystal space group representation, has been worked out in great detail. Since particular phase transitions in crystals often call for a subtle symmetry analysis, the Landau method has been continually refined and developed over the past ten or fifteen years.

In this volume new group-theoretical methods for investigating phase transitions and symmetry problems in various types of crystals and liquid crystals are presented. New topics pertaining to the area of application of the theories of Landau and Birman, such as, transitions to modulated structures and the description of their symmetry, are discussed. Examples of applications of the group-theoretical methods are given, containing detailed calculations of symmetry changes at structural, magnetic, improper ferroelectric, commensurate-to-incommensurate, field-induced metamagnetic and liquid crystal phase transitions. This book will be invaluable to research workers at universities and scientific laboratories and postgraduate students specializing in solid state theory.

In the nematic liquid crystal phase, rod-shaped molecules move randomly but remain essentially parallel to one another. Biaxial nematics, which were first predicted in 1970 by Marvin Freiser, have their molecules differentially oriented along two axes. They have the potential to create displays with fast switching times and may have applications in thin-film displays and other liquid crystal technologies. This book is the first to be concerned solely with biaxial nematic liquid crystals, both lyotropic and thermotropic, formed by low molar mass as well as polymeric systems. It opens with a general introduction to the biaxial nematic phase and covers: • Order parameters and distribution functions • Molecular field theory • Theories for hard biaxial particles • Computer simulation of biaxial nematics • Alignment of the phase • Display applications • Characterisation and identification • Lyotropic, thermotropic and colloidal systems together with material design With a consistent, coherent and pedagogical approach, this book brings together theory, simulations and experimental studies; it includes contributions from some of the leading figures in the field. It is relevant to students and researchers as well as to industry professionals working in soft matter, liquid crystals, liquid crystal devices and their applications throughout materials science, chemistry, physics, mathematics and display engineering.

This book describes how the arrangement and movement of atoms in a solid are related to the forces between atoms, and how they affect the behaviour and properties of materials. The book is intended for final year undergraduate students and graduate students in physics and materials science.

Bridge the gap between thermodynamic theory and engineering practice with this essential textbook Thermodynamics is a discipline which straddles the fields of chemistry, physics, and engineering, and has long been a mainstay of undergraduate and graduate curricula. Conventional thermodynamics courses, however, often ignore modern developments in statistical mechanics, such as molecular simulation methods, cooperative phenomena, phase transitions, universality, as well as liquid-state and polymer theories, despite their close relevance to both fundamental research and engineering practice. Fundamentals and Practice in Statistical Thermodynamics fills this gap with an essential book that applies up-to-date statistical-mechanical techniques to address the most crucial thermodynamics problems found in chemical and materials systems. It is ideally suited to introduce a new generation of researchers and molecular engineers to modern thermodynamic topics with numerous cutting-edge applications. From Fundamentals and Practice in Statistical Thermodynamics readers will also find: An introduction to statistical-mechanical methods including molecular dynamics simulation, Monte Carlo simulation, as well as the molecular theories of phase transitions, classical fluids, electrolyte solutions, polymeric materials, and more Illustrative examples and exercise problems with solutions to facilitate student understanding Supplementary online materials covering the basics of quantum mechanics, density functional theory, variational principles of classical mechanics, intermolecular interactions, and many more subjects Fundamentals and Practice in Statistical Thermodynamics is ideal for graduate and advanced undergraduate students in chemical engineering, biomolecular engineering, environmental engineering, materials science and engineering, and all related scientific subfields of physics and chemistry.

This book deals with the phenomenological theory of first-order structural phase transitions, with a special emphasis on reconstructive transformations in which a group-subgroup relationship between the symmetries of the phases is absent. It starts with a unified presentation of the current approach to first-order phase transitions, using the more recent results of the Landau theory of phase transitions and of the theory of singularities. A general theory of reconstructive phase transitions is then formulated, in which the structures surrounding a transition are expressed in terms of density-waves, providing a natural definition of the transition order-parameters, and a description of the corresponding phase diagrams and relevant physical properties. The applicability of the theory is illustrated by a large number of concrete examples pertaining to the various classes of reconstructive transitions: allotropic transformations of the elements, displacive and order-disorder transformations in metals, alloys and related structures, crystal-quasicrystal transformations.

A 2006 edition explaining the underlying science and applications of liquid crystalline polymers.