Mesoscopic effects in adiabatic spin pumping

TL;DR

This paper investigates how modulating the shape of a quantum dot in the presence of spin-orbit coupling can generate a direct current of spin, with the polarization direction depending on the coupling strength, and analyzes the statistical behavior across different coupling regimes.

Contribution

It provides a detailed analysis of mesoscopic effects in adiabatic spin pumping, including the crossover from weak to strong spin-orbit coupling and the resulting spin current polarization.

Findings

Finite dc spin current generated by shape modulations.

Spin polarization direction varies with spin-orbit coupling strength.

Statistical analysis of spin and charge currents across coupling regimes.

Abstract

We show that temporal shape modulations (pumping) of a quantum dot in the presence of spin-orbital coupling lead to a finite dc spin current. Depending on the strength of the spin-orbit coupling, the spin current is polarized perpendicular to the plane of the two-dimensional electron gas, or has an arbitrary direction subject to mesoscopic fluctuations. We analyze the statistics of the spin and charge currents in the adiabatic limit for the full cross-over from weak to strong spin-orbit coupling.