Optical injection of spin currents in bulk and quantum well semiconductors.
Contributors: Sipe, John (supervisor).
Published: 2005
Language: eng
Number of pages: 154
Subjects: Physics Theses.
Description: Spin-orbit coupling is a relativistic effect, where an electric field in the lab frame is Lorentz transformed to a magnetic field in the rest frame of a moving charged particle. This magnetic field interacts with the spin of the carrier. Spin-orbit interaction couples the translational and spin degrees of freedom. If a system lacks inversion symmetry, by definition, the "right" and "left" going carriers with wavevectors +/-k feel a different electric field landscape, and hence have different spin-properties, because of spin-orbit coupling. This thesis is based on the above principles, and focuses on optical manipulation of spins in semiconductors, with the aim of all-optical generation and control of spin currents in a semiconductors. Aspects of two distinct methods for injecting spin currents in bulk and quantum well semiconductors are discussed.Quantum interference between one and two photon absorption can be used to inject and control spin and charge currents in the plane of a quantum well. Moreover, strain can be used to obtain and maintain large degrees of spin polarization. It is also shown that ejection of spins from a quantum well can be controlled using quantum interference. In both cases, the spin currents can be with or without an accompanying charge current and can be controlled using a relative phase parameter of the optical fields.A general method for injecting spin currents in doped noncentrosymmetric semiconductors, via spin-flip Raman scattering, is introduced. In particular, spin-flip stimulated Raman scattering can be used to inject pure spin currents in bulk zincblende doped semiconductors. A pure spin current does not have an accompanying charge current. It is also argued that pure spin currents can be injected in the plane of a quantum well, using Raman scattering. Furthermore, characteristics of the injected spin current can be controlled by external means, such as an electric field across the quantum well.
Notes: Source: Dissertation Abstracts International, Volume: 66-10, Section: B, page: 5462.

Thesis (Ph.D.)--University of Toronto, 2005.

Electronic version licensed for access by U. of T. users.