ALL-ELECTRICAL SPIN CONTROL IN A TRIPLE-TERMINAL QUANTUM DOTS RING: EFFECT OF THE INTERDOT COUPLING AND SPIN FLIP

摘要

The electron spin polarization in two quantum dots, which are inserted in one arm of a mesoscopic ring, is investigated by means of the non-equilibrium Keldysh Green’s function technique. We find that the spin accumulations in the two dots Δn_i = n_i↑ Δni↓, where niσ is the spin-σ electron occupation number in dot i, can be efficiently tuned in terms of the applied bias voltage V , the interdot tunneling coupling strength tc and the phase induced by the Rashba spin-orbit interaction. By adjusting these parameters, Δn_1 and Δn_2 can be generated and manipulated either simultaneously or separately, which may have real usage in spintronics or quantum information devices. We interpret the origin of the spin accumulation in terms of the spin-dependent total effective coupling strengths between the leads and the dots.