Pumping spin with electrical fields

TL;DR

This paper demonstrates how electrical gating can induce spin currents via adiabatic pumping in semiconductor heterostructures with tunable Rashba spin-orbit coupling, supported by theoretical and realistic structure analysis.

Contribution

It introduces a method for generating spin currents through electrical control of Rashba coupling in multi-channel structures, including disorder effects and detection strategies.

Findings

Spin currents can be pumped electrically in semiconductor wires.

The effect persists in multi-channel, disordered structures.

Detection methods include ferromagnetic leads and magnetic fields.

Abstract

Spin currents can be obtained through adiabatic pumping by means of electrical gating only. This is possible by making use of the tunability of the Rashba spin-orbit coupling in semiconductor heterostructures. We demonstrate the principles of this effect by considering a single-channel wire with a constriction. We also consider realistic structures, consisting of several open channels where subband spin-mixing and disorder are present, and we confirm our predictions. Two different ways to detect the spin-pumping effect, either using ferromagnetic leads or applying a magnetic field, are discussed.