Toward The Controllable Quantum States: Mesoscopic Superconductivity And Spintronics


Book Description

The realizations of physical systems whose quantum states can be directly manipulated have been pursued for experiments on fundamental problems in quantum mechanics and implementations of quantum information devices. Micro-fabricated superconducting systems and electronic spins are among the most promising candidates. This book contains the newest and most advanced research reports on such materials, called “Mesoscopic Superconductivity” and “Spintronics”. The former includes superconductor-semiconductor hybrid systems, very small Josephson junctions, and micron-size SQUIDs. The latter includes the control of spin transports in semiconductor heterostructures, nano-scale quantum dots, and spin injections. Superconductor-ferromagnetic metal hybrid structures are covered by both of the topics.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)




Spintronics


Book Description

A sound understanding of magnetism, transport theory, spin relaxation mechanisms, and magnetization dynamics is necessary to engage in spintronics research. In this primer, special effort has been made to give straightforward explanations for these advanced concepts. This book will be a valuable resource for graduate students in spintronics and related fields. Concepts of magnetism such as exchange interaction, spin-orbit coupling, spin canting, and magnetic anisotropy are introduced. Spin-dependent transport is described using both thermodynamics and Boltzmann’s equation, including Berry curvature corrections. Spin relaxation phenomenology is accounted for with master equations for quantum spin systems coupled to a bath. Magnetic resonance principles are applied to describe spin waves in ferromagnets, cavity-mode coupling in antiferromagnets, and coherence phenomena relevant to spin qubits applications. Key Features: • A pedagogical approach to foundational concepts in spintronics with simple models that can be calculated to enhance understanding. • Nineteen chapters, each beginning with a historical perspective and ending with an outlook on current research. • 1200 references, ranging from landmark papers to frontline publications. Jean-Philippe Ansermet is Professor Emeritus at École Polytechnique Fédérale de Lausanne (EPFL), where he pioneered experiments on giant magnetoresistance, current-induced magnetization switching, heat-driven spin torque, and nuclear magnetic resonance. He taught mechanics, thermodynamics, and spin dynamics for more than twenty years. A fellow of the American Physical Society and recipient of the 2022 Credit Suisse Teaching Award, he was an executive board member of the European Physical Society, president of the Swiss Physical Society, and teaching director at EPFL. He has authored or co-authored textbooks on mechanics and thermodynamics and published more than two hundred articles.




Semiconductor Spintronics and Quantum Computation


Book Description

The past few decades of research and development in solid-state semicon ductor physics and electronics have witnessed a rapid growth in the drive to exploit quantum mechanics in the design and function of semiconductor devices. This has been fueled for instance by the remarkable advances in our ability to fabricate nanostructures such as quantum wells, quantum wires and quantum dots. Despite this contemporary focus on semiconductor "quantum devices," a principal quantum mechanical aspect of the electron - its spin has it accounts for an added quan largely been ignored (except in as much as tum mechanical degeneracy). In recent years, however, a new paradigm of electronics based on the spin degree of freedom of the electron has begun to emerge. This field of semiconductor "spintronics" (spin transport electron ics or spin-based electronics) places electron spin rather than charge at the very center of interest. The underlying basis for this new electronics is the intimate connection between the charge and spin degrees of freedom of the electron via the Pauli principle. A crucial implication of this relationship is that spin effects can often be accessed through the orbital properties of the electron in the solid state. Examples for this are optical measurements of the spin state based on the Faraday effect and spin-dependent transport measure ments such as giant magneto-resistance (GMR). In this manner, information can be encoded in not only the electron's charge but also in its spin state, i. e.




Macroscopic Quantum Coherence and Quantum Computing


Book Description

This volume is an outgrowth of the Second International Workshop on Macroscopic Quantum Coherence and Computing held in Napoli, Italy, in June 2000. This workshop gathered a number of experts from the major Universities and Research Institutions of several countries. The choice of the location, which recognizes the role and the traditions of Naples in this field, guaranteed the participants a stimulating atmosphere. The aim of the workshop has been to report on the recent theoretical and experimental results on the macroscopic quantum coherence of macroscopic systems. Particular attention was devoted to Josephson devices. The correlation with other atomic and molecular systems, exhibiting a macroscopic quantum behaviour, was also discussed. The seminars provided both historical overview and recent theoretical ground on the topic, as well as information on new experimental results relative to the quantum computing area. The first workshop on this topic, held in Napoli in 1998, has been ennobled by important reports on observations of Macroscopic Quantum Coherence in mesoscopic systems. The current workshop proposed, among many stimulating results, the first observations of Macroscopic Quantum Coherence between macroscopically distinct fluxoid states in rf SQUIDs, 20 years after the Leggett's proposal to experimentally test the quantum behavior of macroscopic systems. Reports on observations of quantum behaviour in molecular and magnetic systems, small Josephson devices, quantum dots have also been particularly stimulating in view of the realization of several possible q-bits.




Spintronics


Book Description

Starting from quantum mechanical and condensed matter foundations, this book introduces into the necessary theory behind spin electronics (Spintronics). Equations of spin diffusion, -evolution and -tunelling are provided before an overview is given of simulation of spin transport at the atomic scale. Furthermore, applications are discussed with a focus on elementary spintronics devices such as spin valves, memory cells and hard disk heads.




Quantum Phenomena in Mesoscopic Systems


Book Description

This book is a snapshot of the vision shared by outstanding scientists on the key theoretical and experimental issues in Mesoscopic Physics. Quantum properties of electrons in solid state devices and transport in semiconducting and superconducting low-dimensional systems, are discussed, as well as the basis of quantum computing (entanglement, noise decoherence and read-out). Each chapter collects the material presented at a Varenna School course of last year, by leading experts in the field. The reader gets a flavor, how theorists and experimentalists are paving the way to the physical realization of solid state qubits, the basic units of the new logic and memory elements for quantum processing. He will be surprised in finding that mesoscopic solid state devices, which were invented just yesterday ( think of the Single Electron Transistor, or the Cooper Pair Box) are currently used as charge-sensing applications in the equipment of frontier research laboratories. These devices contribute as probing systems to produce evidence on still unsettled questions in topics like the metal-insulator transition in disordered two dimensional systems, quantum Hall conductance in heterostructures, or Kondo conductance in quantum dots.




Functional Nanostructures and Metamaterials for Superconducting Spintronics


Book Description

This book demonstrates how the new phenomena in the nanometer scale serve as the basis for the invention and development of novel nanoelectronic devices and how they are used for engineering nanostructures and metamaterials with unusual properties. It discusses topics such as superconducting spin-valve effect and thermal spin transport, which are important for developing spintronics; fabrication of nanostructures from antagonistic materials like ferromagnets and superconductors, which lead to a novel non-conventional FFLO-superconducting state; calculations of functional nanostructures with an exotic triplet superconductivity, which are the basis for novel nanoelectronic devices, such as superconducting spin valve, thin-film superconducting quantum interference devices (SQUIDs) and memory-elements (MRAM). Starting with theoretical chapters about triplet superconductivity, the book then introduces new ideas and approaches in the fundamentals of superconducting electronics. It presents various quantum devices based on the new theoretical approaches, demonstrating the enormous potential of the electronics of 21st century - spintronics. The book is useful for a broad audience, including researchers, engineers, PhD graduates, students and others wanting to gain insights into the frontiers of nanoscience.




Spin Electronics


Book Description

The history of scientific research and technological development is replete with examples of breakthroughs that have advanced the frontiers of knowledge, but seldom does it record events that constitute paradigm shifts in broad areas of intellectual pursuit. One notable exception, however, is that of spin electronics (also called spintronics, magnetoelectronics or magnetronics), wherein information is carried by electron spin in addition to, or in place of, electron charge. It is now well established in scientific and engineering communities that Moore's Law, having been an excellent predictor of integrated circuit density and computer performance since the 1970s, now faces great challenges as the scale of electronic devices has been reduced to the level where quantum effects become significant factors in device operation. Electron spin is one such effect that offers the opportunity to continue the gains predicted by Moore's Law, by taking advantage of the confluence of magnetics and semiconductor electronics in the newly emerging discipline of spin electronics. From a fundamental viewpoine, spin-polarization transport in a material occurs when there is an imbalance of spin populations at the Fermi energy. In ferromagnetic metals this imbalance results from a shift in the energy states available to spin-up and spin-down electrons. In practical applications, a ferromagnetic metal may be used as a source of spin-polarized electronics to be injected into a semiconductor, a superconductor or a normal metal, or to tunnel through an insulating barrier.




Introduction to the Physics of Nanoelectronics


Book Description

This book provides an introduction to the physics of nanoelectronics, with a focus on the theoretical aspects of nanoscale devices. The book begins with an overview of the mathematics and quantum mechanics pertaining to nanoscale electronics, to facilitate the understanding of subsequent chapters. It goes on to encompass quantum electronics, spintronics, Hall effects, carbon and graphene electronics, and topological physics in nanoscale devices.Theoretical methodology is developed using quantum mechanical and non-equilibrium Green's function (NEGF) techniques to calculate electronic currents and elucidate their transport properties at the atomic scale. The spin Hall effect is explained and its application to the emerging field of spintronics – where an electron's spin as well as its charge is utilised – is discussed. Topological dynamics and gauge potential are introduced with the relevant mathematics, and their application in nanoelectronic systems is explained. Graphene, one of the most promising carbon-based nanostructures for nanoelectronics, is also explored. - Begins with an overview of the mathematics and quantum mechanics pertaining to nanoscale electronics - Encompasses quantum electronics, spintronics, Hall effects, carbon and graphene electronics, and topological physics in nanoscale devices - Comprehensively introduces topological dynamics and gauge potential with the relevant mathematics, and extensively discusses their application in nanoelectronic systems




An Introduction to Quantum Spin Systems


Book Description

The topic of lattice quantum spin systems is a fascinating and by now well established branch of theoretical physics. Based on a set of lectures, this book has a level of detail missing from others, and guides the reader through the fundamentals of the field.