Low temperature spintronics : probing charge and spin states with two-dimensional electron gas

This thesis is based on two low temperature experiments in spintronics - physics and engineering of electronic spins. The measurements were performed on a GaAs/AlGaAs two-dimensional electron gas with geometries defined by tunable surface gates. The first experiment is about detection of electrons i...

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Main Author: Yu, Wing Wa
Format: Others
Language:English
Published: University of British Columbia 2009
Online Access:http://hdl.handle.net/2429/12580
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spelling ndltd-UBC-oai-circle.library.ubc.ca-2429-125802018-01-05T17:23:41Z Low temperature spintronics : probing charge and spin states with two-dimensional electron gas Yu, Wing Wa This thesis is based on two low temperature experiments in spintronics - physics and engineering of electronic spins. The measurements were performed on a GaAs/AlGaAs two-dimensional electron gas with geometries defined by tunable surface gates. The first experiment is about detection of electrons in a quantum dot. A quantum point contact (QPC) and a quantum wire (QW) is coupled to a single-lead few-electron quantum dot. By measuring the conductance of the QPC and the QW, one can gain information on the average number of electrons in the dot as well as energy-level structure of the dot. The second experiment investigates anisotropy of spin-orbit interaction in GaAs/AlGaAs heterostructure by measuring spin polarization in a narrow channel. Polarized electrons are injected into the channel through a spin-selective injector QPC and diffuse towards the end of the channel. This diffusion generates a pure spin current and the spin polarization 25 microns away is measured by a detector QPC. A periodic spin-orbit field induced by motion of the electrons in the channel causes the spins to resonate with external magnetic field. Spin-orbit anisotropy is demonstrated by the different resonance strength observed in channels aligned along two different crystal axes. Science, Faculty of Physics and Astronomy, Department of Graduate 2009-08-27T13:36:05Z 2009-08-27T13:36:05Z 2009 2009-11 Text Thesis/Dissertation http://hdl.handle.net/2429/12580 eng Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ 1297593 bytes application/pdf University of British Columbia
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language English
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description This thesis is based on two low temperature experiments in spintronics - physics and engineering of electronic spins. The measurements were performed on a GaAs/AlGaAs two-dimensional electron gas with geometries defined by tunable surface gates. The first experiment is about detection of electrons in a quantum dot. A quantum point contact (QPC) and a quantum wire (QW) is coupled to a single-lead few-electron quantum dot. By measuring the conductance of the QPC and the QW, one can gain information on the average number of electrons in the dot as well as energy-level structure of the dot. The second experiment investigates anisotropy of spin-orbit interaction in GaAs/AlGaAs heterostructure by measuring spin polarization in a narrow channel. Polarized electrons are injected into the channel through a spin-selective injector QPC and diffuse towards the end of the channel. This diffusion generates a pure spin current and the spin polarization 25 microns away is measured by a detector QPC. A periodic spin-orbit field induced by motion of the electrons in the channel causes the spins to resonate with external magnetic field. Spin-orbit anisotropy is demonstrated by the different resonance strength observed in channels aligned along two different crystal axes. === Science, Faculty of === Physics and Astronomy, Department of === Graduate
author Yu, Wing Wa
spellingShingle Yu, Wing Wa
Low temperature spintronics : probing charge and spin states with two-dimensional electron gas
author_facet Yu, Wing Wa
author_sort Yu, Wing Wa
title Low temperature spintronics : probing charge and spin states with two-dimensional electron gas
title_short Low temperature spintronics : probing charge and spin states with two-dimensional electron gas
title_full Low temperature spintronics : probing charge and spin states with two-dimensional electron gas
title_fullStr Low temperature spintronics : probing charge and spin states with two-dimensional electron gas
title_full_unstemmed Low temperature spintronics : probing charge and spin states with two-dimensional electron gas
title_sort low temperature spintronics : probing charge and spin states with two-dimensional electron gas
publisher University of British Columbia
publishDate 2009
url http://hdl.handle.net/2429/12580
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