Download or read book Optical Polarization of Nuclear Spins in Gallium Arsenide written by Anant Krishna Paravastu and published by . This book was released on 2004 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Optically Pumped Nuclear Magnetic Polarization on Gallium Arsenide written by Yunpu Li and published by . This book was released on 2012 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aims to study the dynamic process of optically pumped nuclear spin polarization on Gallium Arsenide. First of all, the time-resolved optical Faraday rotation is applied to observe the electron spin dynamics in the presence of the nuclear magnetic field. And then the optically-pumped NMR is measured on different parameters, including the dependences of light helicity, irradiation intensity, photon energy, illumination time and temperature. We report a new phenomenology at low irradiation intensity. A nuclear polarization model combining hyperfine and quadrupolar relaxation is developed, with experimental data supported. By exploiting the two competing mechanism on various photon energies, illumination intensity and NMR pulse sequences, we use high field stray-field NMR imaging to realize all-optical creation of three-dimensional patterning of positive and negative nuclear polarization on the micron length scale. Finally, the effect of nuclear spin diffusion effect is investigated. We demonstrate in a remarkable way the unambiguous evidence of diffusion, which results in a great enhancement of quadrupolar relaxation in the nanometer scale.
Download or read book Model for Optically induced Nuclear Spin Polarization in GaAs written by Patrick Joseph Coles and published by . This book was released on 2008 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Orientation of Nuclear Spins written by Jonathan Patrick King and published by . This book was released on 2012 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear spins are harnessed in many important technologies, including the well established fields of magnetic resonance imaging for medical diagnostics, magnetic resonance spectroscopy in analytical chemistry as well as emerging technologies in quantum information and spintronics. All of these technologies either harness, or are subject to, the behavior of a nuclear spin ensemble. To achieve the most desirable behavior, (large spectroscopic signal or reduction of unwanted fluctuations) the nuclear spin ensemble should be prepared in a pure quantum state. In practice, this "polarization" is typically created by allowing the energy levels of the spins in an applied magnetic field achieve thermal equilibrium. Unfortunately, even with the largest magnets available with fields greater than 20 Tesla, the separation between energy levels is much smaller than kT for all but extreme refrigerated systems. It is then desirable to achieve pure nuclear spin states which are not at thermal equilibrium with the environment. In order to do this, it is necessary to create a situation in which a pure quantum state can be created in a system other than the nuclear spin which then interacts with the nucleus to create a more pure nuclear spin state. In this work we harness the pure photon spin state of circularly polarized light as well as spin transition selection rules of a deep electronic defect in diamond to polarize nuclei. In the first case, we use circularly polarized photons to excite spin polarized electrons in the semiconductor gallium arsenide which equilibrate with bound electronic states at recombination centers. These bound states then polarize nearby nuclear spins through the magnetic hyperfine interaction. While this hyperfine mechanism of nuclear spin polarization was previously known, we have identified a new regime of low optical absorption where the coupling of nuclear quadrupole moments to electric field gradients near recombination centers is the dominant mechanism of nuclear spin polarization. Through a combination of experiment and theory, we determine relative rates of these two mechanisms depending on the rate of optical absorption. Since optical absorption varies as a function of depth in a sample, we predicted that control of these two mechanisms is possible as a function of position in the sample. Using the stray field of a superconducting magnet to supply the gradient field for magnetic resonance imaging, we were able to directly observe patterns of nuclear magnetization on a micron length scale. When combined with in-plane control of the laser and NMR pulse sequences, this technique will give rise to fully 3-dimensional patterns of nuclear magnetization. These patterns may be created in bulk gallium arsenide without the need for lithography or other microfabrication techniques. These regions of magnetized nuclei will enable magnetic control over drifting electrons in future spintronics devices. The paramagnetic nitrogen-vacancy defect in diamond provides a different tool to control nuclei. The ground state spin triplet of this defect may be easily polarized into the Sz=0 state with visible optical illumination. The polarization is due to the symmetry and selection rules within the defect itself and does not require polarized photons. We discovered that, with a sufficient density of defects, the 13C nuclei in the diamond lattice are spontaneously polarized upon illumination of the sample. We attribute this polarization to a highly refrigerated "spin temperature" among the energy levels created by the magnetic dipole interaction of the many spins in the defect ensemble. This energy reservoir is in thermal contact with the 13C nuclei, which are driven to highly athermal spin states. We theoretically investigate the thermodynamics of the defect spin ensemble, first with a two-spin "toy model" and more recently have begun a many-spin theoretical approach. The polarization of nuclei in diamond has application in the quenching of nuclear fluctuations in quantum information systems and as a platform for signal enhancement in magnetic resonance imaging and spectroscopy.
Download or read book Optical Pumping and Photoluminescence Detection of Spin polarized Electrons in Uniaxially Stressed Gallium Arsenide written by Paul Zorabedian and published by . This book was released on 1982 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Near Infrared Optical Manipulation of a GaAs AlGaAs Quantum Well in the Quantum Hall Regime written by Jonathan M. Buset and published by . This book was released on 2008 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Manipulation of Electron Spins Bound to Neutral Donors in GaAs written by Kai-Mei C. Fu and published by . This book was released on 2007 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarized Sources And Targets Proceedings Of The Eleventh International Workshop written by Akihiro Yoshimi and published by World Scientific. This book was released on 2007-04-26 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarized beams and targets have been irreplaceable tools in nuclear and particle physics experiments for a long time and have provided us rich information on the role played by spin-degrees of freedom in the sub-nuclear world. In addition, techniques to obtain large nuclear polarization have recently been applied to new fields such as materials and medical sciences.The scope of these proceedings covers recent progress of state-of-the-art techniques in spin polarization, the cryogenic method, the atomic beam method, the optical pumping method and the nuclear reaction method.
Download or read book Optical Orientation and Femtosecond Spectroscopy of Spin Polarized Holes in Gallium Arsenide written by David James Hilton and published by . This book was released on 2002 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time sequenced Optical Nuclear Magnetic Resonance of Gallium Arsenide written by Steven Keith Buratto and published by . This book was released on 1993 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spins in Optically Active Quantum Dots written by Oliver Gywat and published by John Wiley & Sons. This book was released on 2010-02-01 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling a gap in the literature, this up-to-date introduction to the field provides an overview of current experimental techniques, basic theoretical concepts, and sample fabrication methods. Following an introduction, this monograph deals with optically active quantum dots and their integration into electro-optical devices, before looking at the theory of quantum confined states and quantum dots interacting with the radiation field. Final chapters cover spin-spin interaction in quantum dots as well as spin and charge states, showing how to use single spins for break-through quantum computation. A conclusion and outlook round off the volume. The result is a primer providing the essential basic knowledge necessary for young researchers entering the field, as well as semiconductor and theoretical physicists, PhD students in physics and material sciences, electrical engineers and materials scientists.
Download or read book Electron and Nuclear Spin Dynamics in Semiconductor Nanostructures written by M. M. Glazov and published by . This book was released on 2018 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the main aspects of electron and nuclear spin dynamics in semiconductor nanostructures. It summarizes main results of theoretical and experimental studies of interactions in spin systems, effects of ultrafast spin manipulation by light, phenomena of spin losses, and the physics of the omnipresent spin noise.
Download or read book Muon Probes of Spin polarized Electrons in GaAs written by Koji Yokoyama and published by . This book was released on 2009 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spin Physics in Semiconductors written by Mikhail I. Dyakonov and published by Springer. This book was released on 2017-10-04 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.
Download or read book Best of Soviet Semiconductor Physics and Technology 1989 1990 written by Mikhail Efimovich Levinshte?n and published by World Scientific. This book was released on 1995 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each year a large number of first rate articles on the physics and technology of semiconductor devices, written by Soviet experts in the field, are published. However, due to the lack of exchange and personal contact, most of these, unfortunately, are neglected by many scientists from the United States, Japan as well as Western Europe. Consequently, many important developments in semiconductor physics are missed by the Western world.This book is a serious attempt to bridge the gap between the Soviet and Western scientific communities. Most of all, it is an effort towards facilitating the communication and sharing of knowledge amongst people from different parts of the world. Ultimately, the aim is to contribute towards the building of a better world for all ? one where the knowledge of advanced technology and scientific discoveries is used to improve the quality of life and not the pursuit of selfish mutually destructive behavior. For those in the field who wish to partake in this exchange of knowledge and as a gesture of support for their Soviet counterparts, the reading of this book provides the first step.
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
