Generation of the pure spin current via Auger recombination in Rashba quantum wells

Abstract

We propose new non-optical mechanism of the pure spin current generation via Auger recombination in the quantum wells with Rashba spin-orbit coupling. It is shown that such process is allowed due to interference between the Coulomb matrix elements corresponding to two different transitions during Auger recombination, leading to non-diagonal transversal components of the spin current tensor, JR = Jxy = −Jyx. In the limit of low temperatures the total spin current is proportional to the Rashba constant γR, spin relaxation time τs and the third power of both the concentration n, inverse quantum well width a-1 and Eg-2. Estimations show that typical magnitude of the generated spin current by this way is much greater than the ones obtained using intraband optical excitation mechanisms and comparable with spin currents driven by interband optical excitation, provided that the quantum well bandgap is narrow enough (Eg < 0.5 eV).