Spin-flip process through a quantum dot coupled to ferromagnetic electrodes

TL;DR

This paper investigates how spin-flip processes influence electron transport through a quantum dot connected to ferromagnetic electrodes, revealing effects on conductance, density of states, and Kondo peak splitting, with implications for spin-filter devices.

Contribution

It introduces a detailed analysis of spin-flip effects on quantum dot transport using nonequilibrium Green's functions, highlighting the impact on conductance and Kondo peak splitting.

Findings

Conductance and DOS depend strongly on electrode magnetic configurations.

Spin-flip processes split the Kondo peak into two symmetric peaks.

The peak splitting magnitude depends on the spin-flip parameter R.

Abstract

We study the spin-dependent transport through a quantum dot coupled to two ferromagnetic electrodes using the equation of motion method for the nonequilibrium Green's functions. Our results show that the conductance and the density of states (DOS) are strongly dependent on the configurations of the magnetic electrodes. In parallel configuration of magnetic electrodes the conductance is affected by the spin-flip process and the Coulomb repulsion on the dot. The Kondo peak for spin-dependent transport is splitted into two peaks by the spin-flip process. The locations of the two peaks are symmetric about no spin-flip peak and the separation of the splitting is dependent on the strength of the spin-flip parameter $R$. This effect may be useful to realize the spin-filter device.