Semiclassical Theory of Spin Transport in Metallic and Semiconductor Heterostructures PDF Download
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Author: Yunong Qi
Publisher:
ISBN:
Category : Nanostructures
Languages : en
Pages : 230
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Book Description
Recently, transport properties of magnetic nanostructures have been one of the most active research areas of Condensed Matter Physics. Many emerging scientific issues are not satisfactorily answered. This Thesis will be focused on one of the most important theoretical problems in magnetic nanostructures; namely, it aims at a better understanding of magnetotransport phenomena. Two most common scattering mechanisms, diffusive scattering in the bulk of the layers (or particles) and ballistic scattering at the interface (or boundaries) are believed to be the main sources of magnetoresistance (or resistance). Previously, one usually takes the bulk and interface scattering either ballistically or diffusively, but not both. In a realistic experimental structure, both scatterings exist and they are equally important. A unified theory of spin transport was established by using semiclassical Boltzmann equation approach in this Thesis. This work significantly generalizes previous scattering theories and can be broadly used to understand the magnetotransport properties of a variety of magnetic nanostructures. With this formalism, the interface and bulk scatterings can be successfully treated on equal footing. The conductance and magnetoresistance of a pinhole structure, then, can be calculated. It is found that both conductance and magnetoresistance can be optimized to desired values for magnetic recording application. To extend our model to semiconductor heterostructures, a more generalized, theoretical model has been developed in the study of non-zero magnetic and electric fields effects on spin transport properties. It is found that the spin-diffusion equation for non-equilibrium spin density and spin current density involves a number of new relevant length scales that explicitly depend on the electric and magnetic fields. The set of macroscopic equations can be used to address a very broad range of spin transport problems from magnetic, metallic multilayers to semiconductor heterostructures. The subject of spin transport we have completed is not only fundamentally interesting from the viewpoint of theoretical and material physics, but also greatly important for the development of emerging technology such as magnetic random access memory (MRAM) (which is a novel, non-volatile device and potential use for storing information in the computer), transistor, and possibly quantum computers.
Author: Yunong Qi
Publisher:
ISBN:
Category : Nanostructures
Languages : en
Pages : 230
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Book Description
Recently, transport properties of magnetic nanostructures have been one of the most active research areas of Condensed Matter Physics. Many emerging scientific issues are not satisfactorily answered. This Thesis will be focused on one of the most important theoretical problems in magnetic nanostructures; namely, it aims at a better understanding of magnetotransport phenomena. Two most common scattering mechanisms, diffusive scattering in the bulk of the layers (or particles) and ballistic scattering at the interface (or boundaries) are believed to be the main sources of magnetoresistance (or resistance). Previously, one usually takes the bulk and interface scattering either ballistically or diffusively, but not both. In a realistic experimental structure, both scatterings exist and they are equally important. A unified theory of spin transport was established by using semiclassical Boltzmann equation approach in this Thesis. This work significantly generalizes previous scattering theories and can be broadly used to understand the magnetotransport properties of a variety of magnetic nanostructures. With this formalism, the interface and bulk scatterings can be successfully treated on equal footing. The conductance and magnetoresistance of a pinhole structure, then, can be calculated. It is found that both conductance and magnetoresistance can be optimized to desired values for magnetic recording application. To extend our model to semiconductor heterostructures, a more generalized, theoretical model has been developed in the study of non-zero magnetic and electric fields effects on spin transport properties. It is found that the spin-diffusion equation for non-equilibrium spin density and spin current density involves a number of new relevant length scales that explicitly depend on the electric and magnetic fields. The set of macroscopic equations can be used to address a very broad range of spin transport problems from magnetic, metallic multilayers to semiconductor heterostructures. The subject of spin transport we have completed is not only fundamentally interesting from the viewpoint of theoretical and material physics, but also greatly important for the development of emerging technology such as magnetic random access memory (MRAM) (which is a novel, non-volatile device and potential use for storing information in the computer), transistor, and possibly quantum computers.
Author: Tomasz Blachowicz
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110490633
Category : Science
Languages : en
Pages : 302
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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.
Author: Abdel Isakovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 398
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Book Description
Author: El-Saba, Muhammad
Publisher: IGI Global
ISBN: 1522523138
Category : Technology & Engineering
Languages : en
Pages : 690
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Book Description
Rapid developments in technology have led to enhanced electronic systems and applications. When utilized correctly, these can have significant impacts on communication and computer systems. Transport of Information-Carriers in Semiconductors and Nanodevices is an innovative source of academic material on transport modelling in semiconductor material and nanoscale devices. Including a range of perspectives on relevant topics such as charge carriers, semiclassical transport theory, and organic semiconductors, this is an ideal publication for engineers, researchers, academics, professionals, and practitioners interested in emerging developments on transport equations that govern information carriers.
Author: Evgeny Y. Tsymbal
Publisher: CRC Press
ISBN: 1439803781
Category : Science
Languages : en
Pages : 797
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Book Description
In the past several decades, the research on spin transport and magnetism has led to remarkable scientific and technological breakthroughs, including Albert Fert and Peter Grunberg's Nobel Prize-winning discovery of giant magnetoresistance (GMR) in magnetic metallic multilayers. Handbook of Spin Transport and Magnetism provides a comprehensive, bal
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The focus of the research performed under this grant has been the investigation of spin transport in magnetic semiconductor heterostructures. The interest in these systems is motivated both by their intriguing physical properties, as the physical embodiment of a spin-polarized Fermi liquid, as well as by their potential applications as spintronics devices. In our work we have analyzed several different problems that affect the spin dynamics in single and bi-layer spin-polarized two-dimensional (2D) systems. The topics of interests ranged from the fundamental aspects of the electron-electron interactions, to collective spin and charge density excitations and spin transport in the presence of the spin-orbit coupling. The common denominator of these subjects is the impact at the macroscopic scale of the spin-dependent electron-electron interaction, which plays a much more subtle role than in unpolarized electron systems. Our calculations of several measurable parameters, such as the excitation frequencies of magneto-plasma modes, the spin mass, and the spin transresistivity, propose realistic theoretical estimates of the opposite-spin many-body effects, in particular opposite-spin correlations, that can be directly connected with experimental measurements.
Author: Evgeny Y. Tsymbal
Publisher: CRC Press
ISBN: 0429784384
Category : Science
Languages : en
Pages : 619
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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.
Author: Evgeny Y. Tsymbal
Publisher: CRC Press
ISBN: 0429750897
Category : Science
Languages : en
Pages : 735
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Book Description
Spintronics Handbook, 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.
Author: Evgeny Y. Tsymbal
Publisher: CRC Press
ISBN: 1439803773
Category : Science
Languages : en
Pages : 809
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Book Description
In the past several decades, the research on spin transport and magnetism has led to remarkable scientific and technological breakthroughs, including Albert Fert and Peter Grünberg’s Nobel Prize-winning discovery of giant magnetoresistance (GMR) in magnetic metallic multilayers. Handbook of Spin Transport and Magnetism provides a comprehensive, balanced account of the state of the art in the field known as spin electronics or spintronics. It reveals how key phenomena first discovered in one class of materials, such as spin injection in metals, have been revisited decades later in other materials systems, including silicon, organic semiconductors, carbon nanotubes, graphene, and carefully engineered nanostructures. The first section of the book offers a historical and personal perspective of the field written by Nobel Prize laureate Albert Fert. The second section addresses physical phenomena, such as GMR, in hybrid structures of ferromagnetic and normal metals. The third section discusses recent developments in spin-dependent tunneling, including magnetic tunnel junctions with ferroelectric barriers. In the fourth section, the contributors look at how to control spin and magnetism in semiconductors. In the fifth section, they examine phenomena typically found in nanostructures made from metals, superconductors, molecular magnets, carbon nanotubes, quantum dots, and graphene. The final section covers novel spin-based applications, including advanced magnetic sensors, nonvolatile magnetoresistive random access memory, and semiconductor spin-lasers. The techniques and materials of spintronics have rapidly evolved in recent years, leading to vast improvements in hard drive storage and magnetic sensing. With extensive cross-references between chapters, this seminal handbook provides a complete guide to spin transport and magnetism across various classes of materials and structures.
Author: Scott Andrew Bender
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
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Book Description
This thesis advances the theory of quantum and semiclassical transport in magnetic heterostructures. In the solid state, angular momentum can be carried by individual electrons and collective modes. The flow of angular momentum (a spin current), central to the operation of spintronic devices, is generated by the application of electric and magnetic fields and temperature gradients. In what follows, we explore the physics of such nonequilibrium spin currents in magnetic structures, involving an interplay of charge and magnetic dynamics and thermoelectric effects. Chapter 1 provides an introduction to the transport of spin in magnets, carried by electrons and collective excitations of the magnetic order. Chapters 2-6 study the role of thermal fluctuations in transport and magnetic dynamics. In Chapter 2, we describe how incoherent thermal fluctuations of the spin density (magnons), which open inelastic scattering channels, contribute to spin and energy transport between a normal metal and a magnet. Such (temperature-dependent) transport may arise from a thermal gradient applied across the metal/magnet interface or a spin accumulation inside the normal metal and may alter or even drive magnetic dynamics. Chapter 3, is dedicated to the realization of Bose-Einstein condensed magnons (previously observed by microwave pumping) in a normal metal/insulating ferromagnet heterostructure. As is described in Chapter 2, the combination of a temperature gradient and normal metal spin accumulation can drive spin into the insulating ferromagnet, accumulating as magnons; upon reaching a critical density, the magnons, which are bosonic, spontaneously form a quasi-equilibrium condensate. Chapter 4 focuses on thermally driven spin-torques in electrically insulating structures, wherein direct electric control of magnetic dynamics is prohibited. In contrast to the interfacial transport described in Chapter 2, where a spin accumulation is to necessary to observe magnetic dynamics, here we demonstrate how spin-torques can arise from a pure thermal gradient in a heterostructure. These spin-torques can be measured by ferromagnetic resonance and can, under a sufficiently strong bias, actuate magnetic switching. Chapter 5 concerns charge transport in a single-electron transistor, consisting of a magnetic quantum dot in contact with magnetic and normal metal leads. Microwave-driven precession by the dot induces a pumped electric current, which can be enhanced and made highly nonlinear by electron interactions (Coulomb blockade). The dependence of the resulting electrical response on the power and spectrum of microwave irradiation may be utilized to develop nanoscale microwave detectors analogous to single-electron transistor-based electrostatic sensors and nanoelectromechanical devices. In Chapter 6 we study bilayers, composed of a nonmagnetic conducting and a magnetic layer. We develop a general phenomenology for the magnetic and charge dynamics, which are coupled by spin-orbit interactions. In contrast to Chapters 2-4, we focus on the long-wavelength magnetic dynamics, which is subject to current-induced torques and produces fictitious electromotive forces that drive charge dynamics.}
