Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 78 for “"Spin Polarization"”.
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Spin polarization, circular dichroism, and robustness of topological surface states
… untersucht diese Ober ächenzustände mittels spin- und winkelauf- gelöster Photoemissionsspektroskopie. Es wird gezeigt, dass in den Materialien Bi2Se3 und Bi2Te3, in übereinstimmung mit der Literatur, die entscheidenden Charakteristika eines topologischen Ober ächenzustands vorzu nden sind: …
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Spin Polarization of Ground State Electron Gas at Low Densities
… Monte Carlo simulations to study the spontaneous polarization of electron gas at low densities, for both two and three dimensions. Quantum Monte Carlo is a powerful method to tackle many-body Fermion problems, and its high accuracy has been demonstrated in many previous calculations. The methods …
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Tunable spin polarization and conductance anomalies in mesoscopic one-dimensional systems
… accounting for many-body effects and neglecting spin–orbit couplings. Then, with this model, we predict that 1D systems can sustain a hierarchy of spin-polarized configurations which emerge above a carrier concentration threshold and are responsible for the 0.7 anomaly. The basis of our theory is …
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Electrical injection and detection of spin polarization in InSb/ferromagnet nanostructures
We present studies of the electical detection of spin injection and transport in InSb/CoFe heterostructures. As a narrow gap semiconductor, InSb has a high mobility and strong spin-orbit interaction. Using ferromagnetic CoFe, lateral InSb/CoFe devices are fabricated by semiconductor processing …
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Rydberg Time-Of-Flight And Imaging Probes Of The Velocity-Dependent Hydrogen Atom Spin Polarization
<p>Insights into electron spin and nuclei are central to the field of chemical reaction dynamics. Of particular note is the study of spin-polarized hydrogen (SPH) atoms, which result from photodissociation of molecules. Examination of the detailed H-atom spin polarization is achieved by determining …
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Measurement of the Transverse Spin Polarization of the Lambda in Quasi-Real Photoproduction and Electroproduction at HERMES
The mystery of hadron polarization has been a source of both experimental and theoretical interest the last few decades. Measurements of polarizations in such particles as the Lambda particle have been done in proton-proton collisions, but studies in positron-proton scattering with high statistical …
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Two topics in particle accelerator beams: Vlasov-Maxwell treatment of coherent synchrotron radiation and topological treatment of spin polarization
… results from my studies of the dynamics of spin polarized beams. Here the emphasis is on improvements of the theoretical basis of beam simulations by using topological methods.
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Relativistic theory of low energy electron diffraction
In view of investigating the role of spin polarization and further relativistic effects in the diffraction of low energy electrons (LEED) by crystals composed of heavy atoms, a relativistic dynamical theory is developed for calculating LEED intensities and spin polarizations. The presentation of …
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The study of weak ferromagnetism by andreev reflection spin spectroscopy and development of bimorph electro-thermal actuators
<p>It is well accepted that spin polarization of materials has a major role in spintronics to improve the efficiency of spintronic devices. Point contact Andreev reflection (PCAR) spectroscopy, one of the most popular and reliable techniques, was used to obtain the conductance and by analyzing them …
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Half-metallic CrO_2 thin films for spintronic applications
… half-metallic oxide with near perfect spin polarization - known to have the highest spin polarization among all known materials theoretically as well as experimentally. This means that the conduction electrons in CrO_2 have only one kind of spin i.e. conduction is due only to the …
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Pairing and superfluidity in strongly interacting Fermi gases
This thesis describes experiments with superfluid spin mixtures of ultracold fermionic 6Li atoms. The properties of the strongly interacting gas are studied in the crossover regime between Bose-Einstein condensation (BEC) of two-body bound molecules and a Bardeen-Cooper-Schrieffer (BCS) superfluid …
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Using High-Powered, Frequency-Narrowed Lasers For Rb/129Xe and Cs/129Xe Spin-Exchange Optical Pumping To Achieve Improved Production of Highly Spin-Polarized Xenon For Use In Magnetic Resonance Applications
… minute nuclear magnetic moments and low nuclear spin polarization levels at thermal equilibrium (~10-5 to 10-6), and thus necessitates the use of relatively large sample volumes. One way to overcome this low detection sensitivity is to introduce a species with highly non-equilibrium nuclear spin …
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SPECTROSCOPIC STUDIES OF NUCLEAR SPINS POLARIZED VIA SPIN EXCHANGE OPTICAL PUMPING AND DYNAMIC COUPLING IN CRYPTOPHANE HOST-GUEST COMPLEXES
… largely from extremely small (Boltzmann) nuclear spin polarization at thermal equilibrium--in even the strongest of magnets. This dissertation focuses on selected research areas that maybe used to combat the limitations presented by NMR and measure weak spectral responses with atomic-scale …
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Polaron transport in ionic crystals
… reduction, relative freedom from space charge polarization, and higher sensitivity and stability than that of previous designs. Using the new method, measurements were made of Hall effect, hot electron effects and magnetoconductivity in a variety of ionic crystals. The conduction bands of seven …
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Quantum State Singlet-Triplet Character Control in 7Li2
… by all-optical control of valence electron spin polarization in the lithium dimer. The energy levels of interest are two closely spaced rovibrational levels (the G1Πg (12, 21f) and 13Sg- (1, 21f) states separated by 720 MHz). In the absence of any optical fields, the spin-orbit interaction …
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Porphyrin Arrays and Perylene Diimide as Molecular Spintronic Components
… In this regard, the introduction of molecular spintronics brings more versatility to superior efficiency in information processing. Spintronic devices sharply contrast with traditional electronics by exploiting the electron spin degree of freedom in addition to the charge and key to the …
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Ferromagnetism of novel ultrathin films and multilayers: A study of Ru/C(0001) and Fe/Mn/Fe/Pd(100) using magneto-optic Kerr effect and spin-sensitive electron spectroscopies
… surface is studied using electron induced spin-polarized secondary electron emission (SPSEE). Below a surface Curie temperature of approximately 250K we find ferromagnetic order of the Ru monolayer. The growth mode of Ru on C(0001) is investigated by Auger electron spectroscopy (AES). We …
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Theoretical Investigations of the Electronic, Magnetic, and Thermoelectric Properties of Transition-Metal Based Compounds
… ferromagnetic materials with full electron spin polarization. The lattice thermal conductivity (κL) was found to decrease for these alloys as the temperature increases. The present investigation indicated that the phonon optical modes have a major contribution to the total κL as compared to …
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Quantum Monte Carlo: Applications of the Twist -Averaged Boundary Conditions and the Calculation of Forces
… 3He and the electronic surface. We studied the spin polarization transition of 3DEG with optimized wavefunctions including backflow and three-body correlations. We found electrons spontaneously polarize at low densities. The transition starts at rs = 55 +/- 5. For 2DEG, we calculated the …
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Investigation of the tunneling emitter bipolar transistor as spin-injector into silicon
… emitter bipolar transistor as a possible spin-injector into silicon. The transistor has a metallic emitter which as a spin-injector will be a ferromagnet. Spin-polarized electrons from the ferromagnet tunnel directly into the conduction band of the base of the transistor and are …
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