Tunable pure spin currents in a triple-quantum-dot ring

TL;DR

This paper theoretically investigates how local Rashba spin-orbit interaction in a triple-quantum-dot ring can generate and control pure spin currents without magnetic fields, with currents tunable by bias voltage and magnetic field.

Contribution

It introduces a method to generate and manipulate pure spin currents in a quantum dot ring using local Rashba interaction and external controls, a novel approach in spintronics.

Findings

Pure spin current can be generated without magnetic fields.

Spin current polarization can be inverted by bias voltage.

Charge and spin currents peak alternately with magnetic field tuning.

Abstract

Electron transport properties in a triple-quantum-dot ring with three terminals are theoretically studied. By introducing local Rashba spin-orbit interaction on an individual quantum dot, we calculate the charge and spin currents in one lead. We find that a pure spin current appears in the absence of a magnetic field. The polarization direction of the spin current can be inverted by altering the bias voltage. In addition, by tuning the magnetic field strength, the charge and spin currents reach their respective peaks alternately.