Kondo effect in quantum dots coupled with noncollinear ferromagnetic leads

D. Matsubayashi, M. Eto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We study the Kondo effect in a quantum dot coupled to two noncollinear ferromagnetic leads. First, we study the spin splitting δε = ε↑ - ε↓ in the quantum dot by the tunnel coupling to the ferromagnetic leads, using the Poor man's scaling method. The spin splitting takes place in an intermediate direction between the polarization directions in the two leads. δε ∞ cos(θ/2), where θ is the angle between the polarization directions; spin splitting is maximal in the parallel alignment of two ferromagnets (θ = 0) and disappears in the antiparallel alignment (θ = π). Second, we calculate the Kondo temperature T K. The scaling calculation yields an analytical expression of T K as a function of θ and polarization ratio p in the ferromagnets, TK (θ,p), when δe << TK. When δe is relevant, we evaluate TK(δε, θ, p) using the slave-boson mean field method. The Kondo resonance is split into two by finite δε, which results in the suppression of Kondo effect.

Original languageEnglish
Title of host publicationMS+S 2006 - Controllable Quantum States
Subtitle of host publicationMesoscopic Superconductivity and Spintronics, Proceedings of the International Symposium
PublisherWorld Scientific Publishing Co. Pte Ltd
Pages227-232
Number of pages6
ISBN (Print)9812814612, 9789812814616
Publication statusPublished - 2008 Jan 1
Event4th International Symposium on Mesoscopic Superconductivity and Spintronics, MS+S 2006 - Atsugi, Japan
Duration: 2006 Feb 272006 Mar 2

Publication series

NameMS+S 2006 - Controllable Quantum States: Mesoscopic Superconductivity and Spintronics, Proceedings of the International Symposium

Other

Other4th International Symposium on Mesoscopic Superconductivity and Spintronics, MS+S 2006
CountryJapan
CityAtsugi
Period06/2/2706/3/2

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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  • Cite this

    Matsubayashi, D., & Eto, M. (2008). Kondo effect in quantum dots coupled with noncollinear ferromagnetic leads. In MS+S 2006 - Controllable Quantum States: Mesoscopic Superconductivity and Spintronics, Proceedings of the International Symposium (pp. 227-232). (MS+S 2006 - Controllable Quantum States: Mesoscopic Superconductivity and Spintronics, Proceedings of the International Symposium). World Scientific Publishing Co. Pte Ltd.