Download or read book Non diffusive Spin Dynamics in a Two dimensional Electron Gas written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs/GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wavevector range from zero to 6 x 104 cm−1. We find that the spin polarization lifetime is maximal at nonzero wavevector, in contrast with expectation based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit coupling.
Download or read book Non diffusive Spin Dynamics in a Two dimensional Electrongas written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe measurements of spin dynamics in thetwo-dimensional electron gas in GaAs/GaAlAs quantum wells. Opticaltechniques, including transient spin-grating spectroscopy, are used toprobe the relaxation rates of spin polarization waves in the wavevectorrange from zero to 6E4 cm-1. We find that the spin polarization lifetimeis maximal at nonzero wavevector, in contrast with expectation based onordinary spin diffusion, but in quantitative agreement with recenttheories that treat diffusion in the presence of spin-orbitcoupling.
Download or read book Handbook of Spin Transport and Magnetism written by Evgeny Y. Tsymbal and published by CRC Press. This book was released on 2016-04-19 with total page 797 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Handbook of Nanophysics written by Klaus D. Sattler and published by CRC Press. This book was released on 2010-09-17 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intensive research on fullerenes, nanoparticles, and quantum dots in the 1990s led to interest in nanotubes and nanowires in subsequent years. Handbook of Nanophysics: Nanotubes and Nanowires focuses on the fundamental physics and latest applications of these important nanoscale materials and structures. Each peer-reviewed chapter contains a broad-
Download or read book Spintronics Handbook Second Edition Spin Transport and Magnetism written by Evgeny Y. Tsymbal and published by CRC Press. This book was released on 2019-05-20 with total page 619 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Spin Dynamics in the Presence of Spin orbit Interactions written by Xin Liu and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We study the spin dynamics in a high-mobility two dimensional electron gas (2DEG) system with generic spin-orbit interactions (SOIs). We derive a set of spin dynamic equations which capture the purely exponential to the damped oscillatory spin evolution modes observed in different regimes of SOI strength. Hence we provide a full treatment of the D'yakonov-Perel's mechanism by using the microscopic linear response theory from the weak to the strong SOI limit. We show that the damped oscillatory modes appear when the electron scattering time is larger than half of the spin precession time due to the SOI, in agreement with recent observations. We propose a new way to measure the scattering time and the relative strength of Rashba and linear Dresselhaus SOIs based on these modes and optical grating experiments. We discuss the physical interpretation of each of these modes in the context of Rabi oscillation. In the finite temperature, We study the spin dynamics in the presence of impurity and electron-electron (e-e) scattering in a III-V semiconductor quantum well. Starting from the Keldysh formalism, we develop the spin-charge dynamic equation at finite temperature in the presence of inelastic scattering which provide a new approach to describe the spin relaxation from the weak to the strong spin-orbit coupling (SOC) regime. In the weak SOC regime, our theory shows that when the system is near the SU(2) symmetry point, because the spin relaxation due to DP mechanism is suppressed dramatically, the spin relaxation is dominated by the Elliott-Yafet (EY) mechanism in a wide temperature regime. The non-monotonic temperature dependence of enhanced-lifetime of spin helix mode is due to the competition between the DP and EY mechanisms. In the strong SOC regime, the our theory is consistent to the previous theoretical results at zero temperature.
Download or read book Random Walk Approach to Spin Dynamics in a Two dimensional Electron Gas with Spin orbit Coupling written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We introduce and solve a semiclassical random walk (RW) model that describes the dynamics of spin polarization waves in zinc-blende semiconductor quantum wells. We derive the dispersion relations for these waves, including the Rashba, linear and cubic Dresselhaus spin-orbit interactions, as well as the effects of an electric field applied parallel to the spin polarization wave vector. In agreement with calculations based on quantum kinetic theory [P. Kleinert and V.V. Bryksin, Phys. Rev. B 76, 205326 (2007)], the RW approach predicts that spin waves acquire a phase velocity in the presence of the field that crosses zero at a nonzero wave vector, q0. In addition, we show that the spin-wave decay rate is independent of field at q0 but increases as (q-q0)2 for q `"q0. These predictions can be tested experimentally by suitable transient spin grating experiments.
Download or read book Spin Dynamics in High mobility Two dimensional Electron Systems Embedded in GaAs AlGaAs Quantum Wells written by Michael Griesbeck and published by . This book was released on 2012 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Symmetry Spin Dynamics And The Properties Of Nanostructures Lecture Notes Of The 11th International School On Theoretical Physics written by Vitalii K Dugaev and published by World Scientific. This book was released on 2015-11-09 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of lecture notes which were presented by invited speakers at the Eleventh School on Theoretical Physics 'Symmetry and Structural Properties of Condensed Matter SSPCM 2014' in Rzeszów (Poland) in September 2014. The main challenge for the lecturers was the objective to present their subject as a review as well as in the form of introduction for beginners. Topics considered in the volume concentrate on: spin dynamics and spin transport in magnetic and non-magnetic structures, spin-orbit interaction in two-dimensional systems and graphene, and new mathematical method used in the condensed matter physics.
Download or read book Spintronics written by Puja Dey and published by Springer Nature. This book was released on 2021-04-13 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book No nonsense Physicist written by Marco Polini and published by Springer. This book was released on 2016-06-30 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a compact personal biography and a collection of works by Gabriele F. Giuliani - a distinguished condensed matter theorist who made important contributions to our understanding of collective effects in electronic materials. In 2012 he passed away after a long battle with cancer. In addition, the book features scientific contributions from some of Prof. Giuliani's former students and collaborators and a number of personal recollections by friends and colleagues which shed light on the complex, multifaceted personality of a physicist who was also a passionate soccer player and formula Ford pilot.
Download or read book Quantum Coherence in Solid State Systems written by Benoît Deveaud and published by IOS Press. This book was released on 2009 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume gives an overview of the manifestations of quantum coherence in different solid state systems, including semiconductor confined systems, magnetic systems, crystals and superconductors. Besides being of paramount importance in fundamental physics, the study of quantum coherence furnishes the starting point for important applications like quantum computing or secure data transmission. The coherent effects discussed mainly involve elementary excitations in solids like polaritons, excitons, magnons, macroscopic quantities like superconductor currents and electron spins. Also, several new aspects of the physics of quasi-particles are understood and discussed in this context. Due to the variety of systems in which quantum coherence may be observed, solid state systems are the natural candidates for applications that rely on coherence, for example quantum computer." --Book Jacket.
Download or read book Electron Spin Dynamics and Hyperfine Interactions in Ferromagnet semiconductor Heterostructures written by Jonathan J. Strand and published by . This book was released on 2004 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spin Current written by Sadamichi Maekawa and published by Oxford University Press. This book was released on 2017 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a new branch of physics and technology, called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called "spin current", are manipulated and controlled together. This book is intended to provide an introduction and guide to the new physics and applications of spin current.
Download or read book Optical Orientation written by F. Meier and published by Elsevier. This book was released on 2012-12-02 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the first systematic exposition of various physical aspects of the orientation of electron and nuclear spins in semiconductors by optical means.
Download or read book Optical Transient grating Measurement of Spin Diffusion and Relaxation in a Two dimensional Electron Gas written by Christopher Phillip Weber and published by . This book was released on 2005 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Doppler Velocimetry of Current Driven Spin Helices in a Two Dimensional Electron Gas written by Luyi Yang and published by . This book was released on 2013 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spins in semiconductors provide a pathway towards the development of spin-based electronics. The appeal of spin logic devices lies in the fact that the spin current is even under time reversal symmetry, yielding non-dissipative coupling to the electric field. To exploit the energy-saving potential of spin current it is essential to be able to control it. While recent demonstrations of electrical-gate control in spin-transistor configurations show great promise, operation at room temperature remains elusive. Further progress requires a deeper understanding of the propagation of spin polarization, particularly in the high mobility semiconductors used for devices. This thesis presents the demonstration and application of a powerful new optical technique, Doppler spin velocimetry, for probing the motion of spin polarization at the level of 1 nm on a picosecond time scale. We discuss experiments in which this technique is used to measure the motion of spin helices in high mobility n-GaAs quantum wells as a function of temperature, in-plane electric field, and photoinduced spin polarization amplitude. We find that the spin helix velocity changes sign as a function of wave vector and is zero at the wave vector that yields the largest spin lifetime. This observation is quite striking, but can be explained by the random walk model that we have developed. We discover that coherent spin precession within a propagating spin density wave is lost at temperatures near 150 K. This finding is critical to understanding why room temperature operation of devices based on electrical gate control of spin current has so far remained elusive. We report that, at all temperatures, electron spin polarization co-propagates with the high-mobility electron sea, even when this requires an unusual form of separation of spin density from photoinjected electron density. Furthermore, although the spin packet co-propagates with the two-dimensional electron gas, spin diffusion is strongly suppressed by electron-electron interactions, leading to remarkable resistance to diffusive spreading of the drifting pulse of spin polarization. Finally, we show that spin helices continue propagate at the same speed as the Fermi sea even when the electron drift velocity exceeds the Fermi velocity of 107 cm s-1. We also use this phase-resolved Doppler velocimetry technique to perform the first simultaneous measurements of drift and diffusion of electron-hole packets in the same two-dimensional electron gas. The results that we obtain strongly violate the picture of electron-hole transport that is presented in the classic textbook treatments of ambipolar dynamics. We find that the rates of transport are controlled almost entirely by the intrinsic frictional force exerted between electrons and holes, rather than the interaction of carriers with phonons or impurities. From the experimental data we obtain the first measurement of the "Coulomb drag" friction between electrons and holes coexisting in the same two-dimensional layer. Moreover, we show that the frictional force thus obtained is in quantitative agreement with theoretically predicted values, which follow entirely from electron density, temperature and fundamental constants, i.e. no adjustable parameters. The understanding of ambipolar transport that we have achieved is an essential prerequisite to the design of those spintronic devices in which spin current is carried by the drift of polarized electrons and holes.
