Electron-Phonon Interaction in Conventional and Unconventional Superconductors


Book Description

The problem of conventional, low-temperature superconductivity has been regarded as solved since the seminal work of Bardeen, Cooper, and Schrieffer (BCS) more than 50 years ago. However, the theory does not allow accurate predictions of some of the most fundamental properties of a superconductor, including the superconducting energy gap on the Fermi surface. This thesis describes the development and scientific implementation of a new experimental method that puts this old problem into an entirely new light. The nominee has made major contributions to the development and implementation of a new experimental method that enhances the resolution of spectroscopic experiments on dispersive lattice-vibrational excitations (the "glue" responsible for Cooper pairing of electrons in conventional superconductors) by more than two orders of magnitude. Using this method,he has discovered an unexpected relationship between the superconducting energy gap and the geometry of the Fermi surface in the normal state, both of which leave subtle imprints in the lattice vibrations that could not be resolved by conventional spectroscopic methods. He has confirmed this relationship on two elemental superconductors and on a series of metallic alloys. This indicates that a mechanism qualitatively beyond the standard BCS theory determines the magnitude and anisotropy of the superconducting gap.




Introduction to Unconventional Superconductivity


Book Description

Unconventional superconductivity (or superconductivity with a nontrivial Cooper pairing) is believed to exist in many heavy-fermion materials as well as in high temperature superconductors, and is a subject of great theoretical and experimental interest. The remarkable progress achieved in this field has not been reflected in published monographs and textbooks, and there is a gap between current research and the standard education of solid state physicists in the theory of superconductivity. This book is intended to meet this information need and includes the authors' original results.




Superconductivity


Book Description

This extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in superconductivity. Covering the entire field, this unparalleled resource carefully blends theoretical studies with experimental results to provide an indispensable foundation for further research. Leading researchers, including Nobel laureates, describe the state of the art in conventional and unconventional superconductors. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued, intense research into electron-phone based superconductivity.




Electron-phonon Interaction And Lattice Dynamics In High Tc Superconductors


Book Description

Understanding the mechanism of the high-temperature superconductors has been a very important topic in condensed matter physics. Researchers have been trying to explain the role of electron-phonon interaction (EPI) in cuprates. Some important properties of the cuprates could not be explained by conventional BCS theory. This book contains the experimental and theoretical studies on the EPI. The experimental part covers the results of angle-resolved photoemission spectroscopy (ARPES), isotopic effect, elastic neutron scattering study of electron-phonon, lattice role and so on. The theoretical part covers the electron-phonon, polaron and bipolaron, effect of lattice, fine structure in the tunnelling spectra of electron-doped cuprates, identification of the bulk pairing symmetry in high-temperature superconductors.Students and researchers interested in high-temperature superconductors, especially the EPI in cuprates will find this title very useful.




Superconductors


Book Description

Unusual and unconventional features of a large variety of novel superconductors are presented and their technological potential as practical superconductors assessed.




Theory of Unconventional Superconductors


Book Description

This book presents a theory for unconventional superconductivity driven by spin excitations. Using the Hubbard Hamiltonian and a self-consistent treatment of the spin excitations, the interplay between magnetism and superconductivity in various unconventional superconductors is discussed. In particular, the monograph applies this theory for Cooper-pairing due to the exchange of spin fluctuations to the case of singlet pairing in hole- and electron-doped high-Tc superconductors, and to triplet pairing in Sr2RuO4. Within the framework of a generalized Eliashberg-like treatment, calculations of both many normal and superconducting properties as well as elementary excitations are performed. The results are related to the phase diagrams of the materials which reflect the interaction between magnetism and superconductivity.




Ultrasonics of High-Tc and Other Unconventional Superconductors


Book Description

Physical Acoustics, Volume XX: Ultrasonics of High-Tc and Other Unconventional Superconductors covers the many acoustic studies of the high-Tc superconductors. This book is composed of 10 chapters that include some unconventional superconducting systems, such as superfluid 3He, heavy Fermion superconductors, and magnetic re-entrant superconductors. The introductory chapter summarizes the results that have been observed in Bardeen, Cooper, and Schriefer superconductors as functions both of temperature and magnetic field. The subsequent chapters deal with the theoretical and experimental aspects of ultrasonic study of some unconventional superconductors. Considerable chapters are devoted to the measurements with sound waves on the sintered high-Tc superconducting systems. These chapters examine first the temperature and magnetic field dependence of the velocity and elastic constants in sintered high-Tc superconductors, as well as the sound absorption and dispersion measurements on single crystals of these superconductors. Discussions on the small-sample resonant ultrasound technique that uses thin piezoelectric films and the effect of oxygen on superconducting properties and the response of sound to these additions are also provided in these chapters. The concluding chapter presents a theoretical foundation for sound measurements in the superconducting state, emphasizing the effects of multigap structures and gas anisotropy on sound attenuation in the superconducting state of the cuprate superconductors. This volume will be of great benefit to researchers in the fields of electronics technology and in applied and engineering mechanics.




Physical Chemistry for Engineering and Applied Sciences


Book Description

This new volume, Physical Chemistry for Engineering and Applied Sciences: Theoretical and Methodological Implications, introduces readers to some of the latest research applications of physical chemistry. The compilation of this volume was motived by the tremendous increase of useful research work in the field of physical chemistry and related subjects in recent years, and the need for communication between physical chemists, physicists, and biophysicists. This volume reflects the huge breadth and diversity in research and the applications in physical chemistry and physical chemistry techniques, providing case studies that are tailored to particular research interests. It examines the industrial processes for emerging materials, determines practical use under a wide range of conditions, and establishes what is needed to produce a new generation of materials. The chapter authors, affiliated with prestigious scientific institutions from around the world, share their research on new and innovative applications in physical chemistry. The chapters in the volume are divided into several areas, covering developments in physical chemistry of modern materials polymer science and engineering nanoscience and nanotechnology




Superconductivity


Book Description

This well-respected and established standard work, which has been successful for over three decades, offers a comprehensive introduction into the topic of superconductivity, including its latest developments and applications. The book has been completely revised and thoroughly expanded by Professor Reinhold Kleiner. By dispensing with complicated mathematical derivations, this book is of interest to both science and engineering students. For almost three decades now, the German version of this book - currently in its sixth edition - has been established as one of the state of the art works on superconductivity.




Superconductivity


Book Description

Superconductivity The third edition of this proven text has been developed further in both scope and scale to reflect the potential for superconductivity in power engineering to increase efficiency in electricity transmission or engines. The landmark reference remains a comprehensive introduction to the field, covering every aspect from fundamentals to applications, and presenting the latest developments in organic superconductors, superconducting interfaces, quantum coherence, and applications in medicine and industry. Due to its precise language and numerous explanatory illustrations, it is suitable as an introductory textbook, with the level rising smoothly from chapter to chapter, such that readers can build on their newly acquired knowledge. The authors cover basic properties of superconductors and discuss stability and different material groups with reference to the latest and most promising applications, devoting the last third of the book to applications in power engineering, medicine, and low temperature physics. An extensive list of more than 350 references provides an overview of the most important publications on the topic. A unique and essential guide for students in physics and engineering, as well as a reference for more advanced researchers and young professionals.