Spin-polarized transport through a parallel triple-quantum-dot device: Blockade effects of Rashba spin-orbit interaction and Coulomb interaction

Abstract

Charge and spin-polarized transport through a parallel coupled triple-quantum-dot (tQD) device with common source and drain electrodes has been theoretically investigated by means of the nonequilibrium Green’s function formalism. By introducing a local Rashba spin-orbit interaction on a QD and considering an Aharonov-Bohm flux through the tQD ring, we find that there is a spin-polarized current (Is) occurring and oscillating in its current-voltage curves. The direction of the spin polarization can be inverted frequently by altering applied bias voltage (V), which turns to result in a multiple negative differential resistance feature in the relationship of (Is-V). Interestingly, a new type of blockade effect, i.e., spin-orbit blockade, different from the Coulomb blockade detected before, has been observed in the charge and spin-polarized currents through the tQD device. Through adjusting these two blockade effects, the tQD device can be designed and applied in the area of spin-current rectifiers and multiple-value logical devices with desirable spin-transport properties.