Kondo effect in a quantum dot coupled to ferromagnetic leads: A numerical renormalization group analysis

TL;DR

This paper uses numerical renormalization group analysis to explore how spin-polarized leads affect the Kondo effect in quantum dots, revealing conditions under which the effect persists or is suppressed.

Contribution

It demonstrates that the Kondo effect can survive finite lead polarizations in certain regimes, challenging previous assumptions about suppression by polarization.

Findings

Kondo effect persists at finite polarization when charge fluctuations are negligible.

Linear tunneling magnetoresistance can serve as an experimental signature.

Spin-flip processes influence the Kondo physics in quantum dots.

Abstract

We investigate the effects of spin-polarized leads on the Kondo physics of a quantum dot using the numerical renormalization group method. Our study demonstrates in an unambiguous way that the Kondo effect is not necessarily suppressed by the lead polarization: While the Kondo effect is quenched for the asymmetric Anderson model, it survives even for finite polarizations in the regime where charge fluctuations are negligible. We propose the linear tunneling magnetoresistance as an experimental signature of these behaviors. We also report on the influence of spin-flip processes.