Adiabatic spin pumping through a quantum dot with a single orbital level

TL;DR

This paper studies adiabatic spin and charge pumping in a quantum dot with a single orbital level, demonstrating tunable spin and charge transfer driven by magnetic field and coupling asymmetry.

Contribution

It introduces a model for adiabatic spin pumping in a quantum dot with a single orbital, highlighting the possibility of pure spin pumping without charge transfer.

Findings

Maximum charge transfer per cycle is e in the absence of a localized moment.

Spin pumping can occur without charge pumping under certain conditions.

Pumped charge and spin are tunable via magnetic field parameters.

Abstract

We investigate an adiabatic spin pumping through a quantum dot with a single orbital energy level under the Zeeman effect. Electron pumping is produced by two periodic time dependent parameters, a magnetic field and a difference of the dot-lead coupling between the left and right barriers of the dot. The maximum charge transfer per cycle is found to be $e$, the unit charge in the absence of a localized moment in the dot. Pumped charge and spin are different, and spin pumping is possible without charge pumping in a certain situation. They are tunable by changing the minimum and maximum value of the magnetic field.