Pumping Current in a Quantum Dot by an Oscillating Magnetic Field

TL;DR

This paper explores how a time-varying magnetic field can induce spin and charge currents in a quantum dot, providing explicit formulas and analysis for optimizing spin current without charge flow.

Contribution

It introduces a density matrix approach to analyze spin and charge pumping in quantum dots under oscillating magnetic fields, offering new insights for experimental optimization.

Findings

Maximal spin current achievable without charge current flow

Explicit expressions for spin and charge currents in terms of system parameters

Analysis of parameter regimes for optimal current pumping

Abstract

We investigate spin and charge current through a quantum dot pumped by a time-varying magnetic field. Using the density matrix method, quantum rate equations for the electronic occupation numbers in the quantum dot are obtained and solved in the stationary state limit for a wide set of setup parameters. Both charge and spin current are expressed explicitly in terms of several relevant parameters and analyzed in detail. The results suggest a way of optimizing experimental setup parameters to obtain an maximal spin current without the charge current flow.