Kondo quantum dot coupled to ferromagnetic leads: Numerical renormalization group study

Abstract

We systematically study the influence of ferromagnetic leads on the Kondo resonance in a quantum dot tuned to the local moment regime. We employ Wilson's numerical renormalization group method, extended to handle leads with a spin asymmetric density of states, to identify the effects of (i) a finite spin polarization in the leads (at the Fermi-surface), (ii) a Stoner splitting in the bands (governed by the band edges) and (iii) an arbitrary shape of the leads density of states. For a generic lead density of states the quantum dot favors being occupied by a particular spin-species due to exchange interaction with ferromagnetic leads leading to a suppression and splitting of the Kondo resonance. The application of a magnetic field can compensate this asymmetry restoring the Kondo effect. We study both the gate-voltage dependence (for a fixed band structure in the leads) and the spin polarization dependence (for fixed gate voltage) of this compensation field for various types of bands. Interestingly, we find that the full recovery of the Kondo resonance of a quantum dot in presence of leads with an energy dependent density of states is not only possible by an appropriately tuned external magnetic field but also via an appropriately tuned gate voltage. For flat bands simple formulas for the splitting of the local level as a function of the spin polarization and gate voltage are given.

18 pages, 18 figures, accepted for publication in PRB

References in corpus (13)

• Kondo effect in quantum dots coupled to ferromagnetic leads
• Theory of Transport through Quantum-Dot Spin Valves in the Weak-Coupling Regime
• NRG study of the Kondo effect in the presence of itinerant-electron ferromagnetism
• Interaction-driven spin precession in quantum-dot spin valves
• Kondo effect in a quantum dot coupled to ferromagnetic leads: A numerical renormalization group analysis
• Numerical Renormalization Group for Quantum Impurities in a Bosonic Bath
• Nonequilibrium spintronic transport through an artificial Kondo impurity: Conductance, magnetoresistance and shot noise
• Gate-controlled spin-splitting in quantum dots with ferromagnetic leads in the Kondo regime
• Nonequilibrium Transport through a Kondo Dot: Decoherence Effects
• Nonequilibrium Kondo Effect in a Quantum Dot Coupled to Ferromagnetic Leads
• Kondo effect with non collinear polarized leads: a numerical renormalization group analysis
• Frequency-dependent transport through a quantum dot in the Kondo regime
• Quantum Dots Attached to Ferromagnetic Leads: Exchange Field, Spin Precession, and Kondo Effect

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