Pure spin currents and associated electrical voltage

TL;DR

This paper develops a generalized transport theory for multi-terminal spin systems with spin-orbit interaction, revealing equilibrium and nonequilibrium pure spin currents that can generate measurable voltages.

Contribution

It introduces a generalized Landauer-Büttiker framework accounting for spin-orbit effects and demonstrates the existence of pure spin currents in a three-terminal device.

Findings

Equilibrium spin currents arise due to spin-orbit interaction.

Pure spin currents can exist without charge currents in a three-terminal setup.

Measured voltage drops can indicate the presence of pure spin currents.

Abstract

We present a generalize Landauer-B\"uttiker transport theory for multi-terminal spin transport in presence of spin-orbit interaction. It is pointed out that the presence of spin-orbit interaction results in {\it equilibrium spin currents}, since in presence of spin-orbit interaction spin is not a conserved quantitative. Further we illustrate the theory by applying it to a three terminal Y-shaped conductor. It is shown that when one of the terminal is a potential probe, there exist {\it nonequilibrium pure spin currents} without a n accompanying charge current. It is shown that this pure spin currents causes a voltage drop which can be measured if the potential probe is ferromagnetic.