Nonlinear dependence on temperature and field of electron spin depolarization in GaAs semiconductors

Abstract

In this work the influence of temperature and drift conditions on the electron spin relaxation in lightly doped n-type GaAs bulk semiconductors is investigated. The electron transport, including the evolution of the spin polarization vector, is simulated by a Monte Carlo procedure which keeps into account all the possible scattering phenomena of the hot electrons in the medium. Electron-spin states in semiconductor structures relax by scattering with imperfections, other carriers and phonons. Spin relaxation lengths and times are computed through the D'yakonov-Perel process since this is the more relevant spin relaxation mechanism in the regime of interest (10 < T < 300 K). The decay of the initial spin polarization of the conduction electrons is calculated as a function of the distance under the presence of a static electric field varying in the range 0.1 - 3 kV/cm. We find that the electron spin relaxation distance and time have a nonmonotonic dependence on both the lattice temperature and the electric field amplitude. Understanding of these phenomena could lead to high temperature and high field engineering of the electron spin memory.