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.




Semiconductor Spintronics


Book Description

This revised and expanded edition of the first comprehensive introduction to the rapidly-evolving field of spintronics covers ferromagnetism in nano-electrodes, spin injection, spin manipulation, and the practical use of these effects in next-generation electronics. Moreover, the book now also includes spin-based optics, topological materials and insulators, and the quantum spin Hall effect.




Molecular Spintronics


Book Description

This thesis targets molecular or organic spintronics and more particularly the spin polarization tailoring opportunities that arise from the ferromagnetic metal/molecule hybridization at interfaces: the new concept of spinterface. Molecular or organic spintronics is an emerging research field at the frontier between organic chemistry and spintronics. The manuscript is divided into three parts, the first of which introduces the basic concepts of spintronics and advantages that molecules can bring to this field. The state of the art on organic and molecular spintronics is also presented, with a special emphasis on the physics and experimental evidence for spinterfaces. The book’s second and third parts are dedicated to the two main experimental topics investigated in the thesis: Self-Assembled Monolayers (SAMs) and Organic Semiconductors (OSCs). The study of SAMs-based magnetic tunnel nanojunctions reveals the potential to modulate the properties of such devices “at will,” since each part of the molecule can be tuned independently like a “LEGO” building block. The study of Alq3-based spin valves reveals magnetoresistance effects at room temperature and is aimed at understanding the respective roles played by the two interfaces. Through the development of these systems, we demonstrate their potential for spintronics and provide a solid foundation for spin polarization engineering at the molecular level.




Spintronics


Book Description

This book highlights the overview of Spintronics, including What is Spintronics ?; Why Do We Need Spintronics ?; Comparative merit-demerit of Spintronics and Electronics ; Research Efforts put on Spintronics ; Quantum Mechanics of Spin; Dynamics of magnetic moments : Landau-Lifshitz-Gilbert Equation; Spin-Dependent Band Gap in Ferromagnetic Materials; Functionality of ‘Spin’ in Spintronics; Different Branches of Spintronics etc. Some important notions on basic elements of Spintronics are discussed here, such as – Spin Polarization, Spin Filter Effect, Spin Generation and Injection, Spin Accumulation, Different kinds of Spin Relaxation Phenomena, Spin Valve, Spin Extraction, Spin Hall Effect, Spin Seebeck Effect, Spin Current Measurement Mechanism, Magnetoresistance and its different kinds etc. Concept of Giant Magnetoresistance (GMR), different types of GMR, qualitative and quantitative explanation of GMR employing Resistor Network Theory are presented here. Tunnelling Magnetoresistance (TMR), Magnetic Junctions, Effect of various parameters on TMR, Measurement of spin relaxation length and time in the spacer layer are covered here. This book highlights the concept of Spin Transfer Torque (STT), STT in Ferromagnetic Layer Structures, STT driven Magnetization Dynamics, STT in Magnetic Multilayer Nanopillar etc. This book also sheds light on Magnetic Domain Wall (MDW) Motion, Ratchet Effect in MDW motion, MDW motion velocity measurements, Current-driven MDW motion, etc. The book deals with the emerging field of spintronics, i.e., Opto-spintronics. Special emphasis is given on ultrafast optical controlling of magnetic states of antiferromagnet, Spin-photon interaction, Faraday Effect, Inverse Faraday Effect and outline of different all-optical spintronic switching. One more promising branch i.e., Terahertz Spintronics is also covered. Principle of operation of spintronic terahertz emitter, choice of materials, terahertz writing of an antiferromagnetic magnetic memory device is discussed. Brief introduction of Semiconductor spintronics is presented that includes dilute magnetic semiconductor, feromagnetic semiconductor, spin polarized semiconductor devices, three terminal spintronic devices, Spin transistor, Spin-LED, and Spin-Laser. This book also emphasizes on several modern spintronics devices that includes GMR Read Head of Modern Hard Disk Drive, MRAM, Position Sensor, Biosensor, Magnetic Field sensor, Three Terminal Magnetic Memory Devices, Spin FET, Race Track Memory and Quantum Computing.




Spintronics


Book Description

This new volume focuses on a new, exciting field of research: Spintronics, the area also known as spin-based electronics. The ultimate aim of researchers in this area is to develop new devices that exploit the spin of an electron instead of, or in addition to, its electronic charge. In recent years many groups worldwide have devoted huge efforts to research of spintronic materials, from their technology through characterization to modeling. The resultant explosion of papers in this field and the solid scientific results achieved justify the publication of this volume. Its goal is to summarize the current level of understanding and to highlight some key results and milestones that have been achieved to date. Semiconductor spintronics is expected to lead to a new generation of transistors, lasers and integrated magnetic sensors that can be used to create ultra-low power, high-speed memory, logic and photonic devices. In addition, development of novel devices such as spin-polarized light emitters, spin field effect transistors, integrated sensors and high-temperature electronics is anticipated. Spintronics has emerged as one of the fastest growing areas of research This text presents an in-depth examination of the most recent technological spintronic developments Includes contributions from leading scholars and industry experts




Semiconductor Quantum Bits


Book Description

This book highlights state-of-the-art qubit implementations in semiconductors and provides an extensive overview of this newly emerging field. Semiconductor nanostructures have huge potential as future quantum information devices as they provide various ways of qubit implementation (electron spin, electronic excitation) as well as a way to transfer quantum information from stationary qubits to flying qubits (photons). Therefore, this book unites contributions from leading experts in the field, reporting cutting-edge results on spin qubit preparation, read-out and transfer. The latest theoretical as well as experimental studies of decoherence in these quantum information systems are also provided. Novel demonstrations of complex flying qubit states and first applications of semiconductor-based quantum information devices are given, too.




Contemporary Topics In Spintronics


Book Description

The success of spintronics — the science and technology of storing, processing, sensing and communicating information using the quantum mechanical spin degree of freedom of an electron — is critically dependent on the ability to inject, detect and manipulate spins in semiconductors either by incorporating ferromagnetic materials into device architectures or by using external magnetic and electric fields. In spintronics, the controlled generation and manipulation of spin polarization in nonmagnetic semiconductors is required for the design of spin-sensitive devices ranging from spin-qubit hosts, quantum memory and gates, quantum teleporters, spin polarizers and filters, spin-field-effect-transistors, and spin-splitters, among others. One of the major challenges of spintronics is to control the creation, manipulation, and detection of spin polarized currents by purely electrical means. Another challenge is to preserve spin coherence in a device for the longest time or over the longest distance in order to produce reliable spintronic processors. These challenges remain daunting, but some progress has been made recently in overcoming some of the steepest obstacles. This book covers some of the recent advances in the field of spintronics using semiconductors.




Spin Physics in Semiconductors


Book Description

The purpose of this collective book is to present a non-exhaustive survey of sp- related phenomena in semiconductors with a focus on recent research. In some sense it may be regarded as an updated version of theOpticalOrientation book, which was entirely devoted to spin physics in bulk semiconductors. During the 24 years that have elapsed, we have witnessed, on the one hand, an extraordinary development in the wonderful semiconductor physics in two dim- sions with the accompanying revolutionary applications. On the other hand, during the last maybe 15 years there was a strong revival in the interest in spin phen- ena, in particular in low-dimensional semiconductor structures. While in the 1970s and 1980s the entire world population of researchers in the ?eld never exceeded 20 persons, now it can be counted by the hundreds and the number of publications by the thousands. This explosive growth is stimulated, to a large extent, by the hopes that the electron and/or nuclear spins in a semiconductor will help to accomplish the dream of factorizing large numbers by quantum computing and eventually to develop a new spin-based electronics, or “spintronics”. Whether any of this will happen or not, still remains to be seen. Anyway, these ideas have resulted in a large body of interesting and exciting research, which is a good thing by itself. The ?eld of spin physics in semiconductors is extremely rich and interesting with many spectacular effects in optics and transport.




Spintronics Handbook, Second Edition: Spin Transport and Magnetism


Book Description

The second edition offers an update on the single most comprehensive survey of the two intertwined fields of spintronics and magnetism, covering the diverse array of materials and structures, including silicon, organic semiconductors, carbon nanotubes, graphene, and engineered nanostructures. It focuses on seminal pioneering work, together with the latest in cutting-edge advances, notably extended discussion of two-dimensional materials beyond graphene, topological insulators, skyrmions, and molecular spintronics. The main sections cover physical phenomena, spin-dependent tunneling, control of spin and magnetism in semiconductors, and spin-based applications.