The Study Of Electron Spin Transport In Semiconductors With Spin-orbit Coupling

In1988the discovery of giant magnetoresistance and subsequent Datta and Das spin field effect transistor was proposed make spintronics became one of the most interesting research fields in condensed matter physics. In recent years, the semiconductors or half metallic materials based on spintronics have attracted a wide spread attention, due to its superiority of integrating spin electronics and traditional semiconductor technology and development of a new generation to spin-based electronics. Spin dependent electron transport is the focus of semiconductor spintronics. In multilayer semiconductors, the electronic transmission coefficient, spin polarizability, conductance and tunneling magnetoresistance were investigated in the presence of Dresselhaus and Rashba spin-orbit coupling with periodic vibration field and under the other conditions. These features can be applied to manipulate electron spin and to use the spin transfer or storage information.This thesis is devoted to the study of the electron transmission in the layered structures composed of non-magnetic semiconductors or magnetic semiconductor/non-magnetic semiconductors with the spin-orbit interaction.(1) We investigate the problem of electronic transmission probability and spin polarizability through double quantum well structure with Dresselhaus spin-orbit coupling and applied oscillating fields in potential well. By the numerical calculations, it is demonstrated that spin-orbit coupling eliminates the spin degeneracy and leads to the splitting of resonance peak. When electron tunnels through the broad potential well, transmission spectra are the symmetric Breit-Wigner resonance peaks, while through the narrow potential well, transmission spectra are the asymmetric Fano resonance peaks. The amplitude and the location of the resonance peaks can be controlled by the incoming energy and the width of the intermediate barrier. These interesting features may be used to devise tunable spin filters to realize the modulation of spin.(2) The electron transmission through a seven-layer semiconductor heterostructure with the Dresselhaus spin-orbit coupling under two applied oscillating fields was investigated. Numerical results show that both of the spin-dependent symmetric Breit-Wigner and the asymmetric Fano resonances appear and that the properties of these two types of resonance peaks are dependent on the amplitude and the relative phases of the two applied oscillating fields.(3) We investigate conductance and tunneling magnetoresistance properties in ballistic spin field-effect transistors by taking into account Desselhaus and Rashba spin-orbit coupling, interface scattering, band mismatch, the polarization angle and the thickness of magnetic semi conduction layer.