TY - GEN

T1 - Kondo effect in quantum dots coupled to ferromagnetic leads

T2 - 28th International Conference on the Physics of Semiconductors, ICPS 2006

AU - Matsubayashi, Daisuke

AU - Eto, Mikio

PY - 2007/12/1

Y1 - 2007/12/1

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

T3 - AIP Conference Proceedings

SP - 805

EP - 806

BT - Physics of Semiconductors - 28th International Conference on the Physics of Semiconductors, ICPS 2006, Part A and B

Y2 - 24 July 2006 through 28 July 2006

ER -