Study On Electron Spin Relaxation And Transmission Properties

Spin relaxation is processes that lead to spin equilibration and are thus of great importance for spintronics. Spin relaxation is of interest from the viewpoints of fundamental physics as well as possible design of quantum spintronic devices and high technological applications. Therefore, the study of spin relaxation has attracted much interest and many experimental and theoretical investigations in the last few years.In this paper, based on the Elliot-Yafet and the D'yakonov-Perel mechanisms, we have calculated theoretically the spin relaxation time of conduction electrons in bulk n-GaAs at the different temperature. Our approach is based upon theoretical calculation of the dominant momentum relaxation rate, we consider the relevant scattering mechanisms such as neutral impurity scattering, ionized impurity scattering, piezoelectric scattering, and optical phonons scattering. The electron spin relaxation time is constructed as a function of the temperature, the electronic energy and the donor/acceptor concentrations. Our results are good agreement with the experimental dates, which allows one to understand the interplay between various factors affecting the spin relaxation process. From the figures, we further show the electron spin relaxation time decreases monotonically with the electronic energy increasing or the donor/acceptor concentrations decreasing, when the temperature remains relatively constant. We predict the theoretical basis for controlling the electron spin relaxation time, through the electronic energy and the donor/acceptor concentrations. It is useful for designing the related spin electric devices.Spintronics based on the electrons spin-orbit coupling in nonmagnetic semiconductor heterostructures has become very popular area of research in the growing field of spintronics recently. The study of the spin-orbit effects, which link the spin and charge dynamics and open the possibility of manipulating electron spin and spin current by means of electric fields without external magnetic in mesoscopic system. It is of critical importance for the design new quantum spintronic devices and quantum information storage. In the paper we take into consideration the Dresselhaus spin-orbit interaction, we study theoretically the transmission coefficients and the traversal time of electrons tunneling through Fe/GaSb/Fe and Fe/InSb/Fe heterostructures. There is a common characteristic for the two different structures, i.e., the transmission coefficients, whether for spin-up spin-down electrons, show obvious resonant features when electrons tunnel through the two heterostructures. We further see that as the length of the semiconductor increases the traversal time of both spin-up and spin-down electrons does not increase linearly but shows steplike behavior, the quantum size effect. Furthermore, we show that the Dresselhaus spin-orbit coupling, unlike Rashba spin-orbit coupling, does not prolong the traversal time of electrons. Because of the different effect of the Dresselhaus spin-orbit coupling on the traversal time of spin-up and spin-down electrons, the difference in the traversal time between spin-up and spin-down electrons can become greater as the length of the semiconductor changes. This is helpful from the device point of view for differentiating spin-up and spin-down electrons and achieving high spin polarizations.