### 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 T_{K} The scaling calculation yields an analytical expression of T_{K} as a function of θ and p, T _{K}(θ,P), when δε << T_{K}. When δε is relevant, we evaluate T_{K}(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 language | English |
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Title of host publication | AIP Conference Proceedings |

Pages | 805-806 |

Number of pages | 2 |

Volume | 893 |

DOIs | |

Publication status | Published - 2007 |

Event | 28th International Conference on the Physics of Semiconductors, ICPS 2006 - Vienna, Austria Duration: 2006 Jul 24 → 2006 Jul 28 |

### Other

Other | 28th International Conference on the Physics of Semiconductors, ICPS 2006 |
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Country | Austria |

City | Vienna |

Period | 06/7/24 → 06/7/28 |

### Fingerprint

### Keywords

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

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*AIP Conference Proceedings*(Vol. 893, pp. 805-806) https://doi.org/10.1063/1.2730135

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

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*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

}

TY - GEN

T1 - Kondo effect in quantum dots coupled to ferromagnetic leads

T2 - Effect of noncollinear magnetization

AU - Matsubayashi, Daisuke

AU - Eto, Mikio

PY - 2007

Y1 - 2007

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.

AB - 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.

KW - Kondo effect

KW - Noncollinear magnetism

KW - Quantum dots

KW - Spin-dependent transport

UR - http://www.scopus.com/inward/record.url?scp=77958486296&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77958486296&partnerID=8YFLogxK

U2 - 10.1063/1.2730135

DO - 10.1063/1.2730135

M3 - Conference contribution

AN - SCOPUS:77958486296

SN - 9780735403970

VL - 893

SP - 805

EP - 806

BT - AIP Conference Proceedings

ER -