Kondo effect in quantum dots coupled to ferromagnetic leads: Effect of noncollinear magnetization

Daisuke Matsubayashi, Mikio 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 magnetic moments in the two leads. δε ∝ p cos(θ/2), where p is the spin polarization in the leads and θ is the angle between the magnetic moments; spin splitting is maximal in the parallel alignment of two ferromagnets (θ = 0) and minimal in the antiparallel alignment (0 = π). Second, we calculate the Kondo temperature TK The scaling calculation yields an analytical expression of TK as a function of θ and p, T K(θ,P), when δε << TK. When δε 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 publicationAIP Conference Proceedings
Pages805-806
Number of pages2
Volume893
DOIs
Publication statusPublished - 2007
Event28th International Conference on the Physics of Semiconductors, ICPS 2006 - Vienna, Austria
Duration: 2006 Jul 242006 Jul 28

Other

Other28th International Conference on the Physics of Semiconductors, ICPS 2006
CountryAustria
CityVienna
Period06/7/2406/7/28

Fingerprint

Kondo effect
quantum dots
magnetization
magnetic moments
alignment
scaling
tunnels
bosons
retarding
polarization
temperature

Keywords

  • Kondo effect
  • Noncollinear magnetism
  • Quantum dots
  • Spin-dependent transport

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Kondo effect in quantum dots coupled to ferromagnetic leads : Effect of noncollinear magnetization. / Matsubayashi, Daisuke; Eto, Mikio.

AIP Conference Proceedings. Vol. 893 2007. p. 805-806.

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

Matsubayashi, D & Eto, M 2007, Kondo effect in quantum dots coupled to ferromagnetic leads: Effect of noncollinear magnetization. in AIP Conference Proceedings. vol. 893, pp. 805-806, 28th International Conference on the Physics of Semiconductors, ICPS 2006, Vienna, Austria, 06/7/24. https://doi.org/10.1063/1.2730135
Matsubayashi, Daisuke ; Eto, Mikio. / Kondo effect in quantum dots coupled to ferromagnetic leads : Effect of noncollinear magnetization. AIP Conference Proceedings. Vol. 893 2007. pp. 805-806
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N2 - 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 magnetic moments in the two leads. δε ∝ p cos(θ/2), where p is the spin polarization in the leads and θ is the angle between the magnetic moments; spin splitting is maximal in the parallel alignment of two ferromagnets (θ = 0) and minimal in the antiparallel alignment (0 = π). Second, we calculate the Kondo temperature TK The scaling calculation yields an analytical expression of TK as a function of θ and p, T K(θ,P), when δε << TK. When δε 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.

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