We extend the hydrodynamic model of the Boltzmann equation by taking into account the spin of the nonequilibrium carriers injected into semiconducting systems. This spin-resolved hydrodynamic description goes beyond the usual drift-diffusion type approaches in a way that the temporal derivatives of the current densities are considered. This allows us to investigate the transient dynamics of spin-polarized packets in the diffusive and ballistic transport regimes. We have properly included the spin-polarized carriers from doping by solving our set of continuity equations and the Poisson equation self-consistently. We determine the spin-polarization landscapes (time and position) of the carrier density (n_↑-n_↓)/(n_↑+n_↓) and the current density (j_↑+j_↓)/(j_↑+j_↓). While in the uniformly doped system the carrier spin polarization has a slow decay, in the nonuniformly doped system it shows a drastic suppression in the interface. In contrast the current spin polarization exhibits an enhancement in this region. It can in principle be useful in designing submicron spintronic devices.
展开▼
