Spin current rectification from a spin-biased quantum dot

TL;DR

This paper calculates the spin current rectification in a quantum dot under spin bias and ac charge bias, revealing peak behaviors related to the dot's energy levels and photon-assisted effects.

Contribution

It introduces a detailed analysis of spin current rectification in quantum dots with a focus on frequency dependence and photon-assisted transport effects.

Findings

Three peaks in rectification coefficient near resonant levels

Peak heights relate to average electron number in the dot

Frequency dependence shows photon-assisted transport effects

Abstract

We compute the spin current rectification coefficient of a non-equilibrium quantum dot subject to a spin bias and an {\it ac} charge bias with small amplitude. As a function of the position of the resonant level the spin current rectification coefficient shows a set of three peaks around the gate voltage at which the resonant or the upper level of the dot is in the vicinity of the equilibrium Fermi level in the leads. The peak heights can be related to the average number of the quantum dot electrons. We discuss the frequency dependence of the spin current rectification coefficient as well and emphasize the effects of the photon-assisted spin transport through the dot.