Effect of a fluctuating electric field on electron spin dephasing in III-V semiconductors

Abstract

In the present work we investigate electron spin relaxation in low-doped n-type GaAs semiconductor bulks driven by a static electric field. The electron dynamics is simulated by a Monte Carlo procedure which keeps into account all the possible scattering phenomena of the hot electrons in the medium and includes the evolution of spin polarization. Spin relaxation lengths are computed through the D’yakonov-Perel process, which is the only relevant relaxation mechanism in zinc-blende semiconductors. Since semiconductor based devices are always imbedded into a noisy environment that can strongly affect their performance, the decay of initial spin polarization of conduction electrons is calculated in the presence of a fluctuating component added to the static driving electric field. The starting point for our analysis is the computation of changes in the depolarization length caused by the addition of an external correlated noise source, at different values of field strength, lattice temperature, doping density, noise amplitude, noise correlation time, etc. Our findings show that, only for values of noise correlation time comparable to the dephasing time, relaxation lengths decrease with the increasing of noise intensity. Moreover, for each value of the noise amplitude, a nonmonotonic behavior of spin depolarization length with the noise correlation time is found. The presence of a minimum is well explained by studying the effective mean electric field experienced by the electrons ensemble within the relaxation time. Furthermore, our study reveals that the system receives a benefit in terms of weakening of the length reduction by the inclusion of the electron-electron scattering mechanism. This effect will be also discussed.