RELAXATION OF ELECTRON SPIN DURING FIELD TRANSPORT IN GaAs BULKS

Abstract

The spin depolarization of drifting electrons in a n-type doped GaAs bulk semiconductor is studied, in a wide range of lattice temperature (40 K < TL < 300 K) and doping density (10^{13} cm^{−3} < n < 10^{16} cm^{−3}), by adopting a semiclassical Monte Carlo approach. The effect of the mechanism of Dyakonov-Perel (DP) on the spin depolarization of the conduction electrons is analyzed as a function of the amplitude of a static electric field, ranging between 0.1 and 6 kV cm^{−1}, by considering the spin dynamics of electrons in both the Γ-valley and the upper L-valleys of the semiconductor. Moreover, the role of the electron-electron scattering mechanism in the suppression of DP spin relaxation is discussed. For high values of the electric field, the strong spin–orbit coupling of electrons in the Γ-valleys significantly reduces the average spin polarization lifetime, but, unexpectedly, for field amplitudes greater than 2.5 kV cm^{−1}, the spin lifetime increases with the lattice temperature. Our numerical findings are validated by a good agreement with the available experimental results and with calculations recently obtained on different semiconductor structures.