Kondo effect in a quantum dot coupled to ferromagnetic leads and side-coupled to a nonmagnetic reservoir

Abstract

Equilibrium transport properties of a single-level quantum dot tunnel-coupled to ferromagnetic leads and exchange-coupled to a side nonmagnetic reservoir are analyzed theoretically in the Kondo regime. The equilibrium spectral functions and conductance through the dot are calculated using the numerical renormalization group (NRG) method. It is shown that in the antiparallel magnetic configuration, the system undergoes a quantum phase transition with increasing exchange coupling $J$, where the conductance drops from its maximum value to zero. In the parallel configuration, on the other hand, the conductance is generally suppressed due to an effective spin splitting of the dot level caused by the presence of ferromagnetic leads, irrespective of the strength of exchange constant. However, for $J$ ranging from J=0 up to the corresponding critical value, the Kondo effect and quantum critical behavior can be restored by applying properly tuned compensating magnetic field.

(8 pages, 8 figs) to appear in PRB

References in corpus (13)

• The numerical renormalization group method for quantum impurity systems
• Observation of the two-channel Kondo effect
• Kondo effect in quantum dots coupled to ferromagnetic leads
• NRG study of the Kondo effect in the presence of itinerant-electron ferromagnetism
• Electric-field controlled spin reversal in a quantum dot with ferromagnetic contacts
• Gate-controlled spin-splitting in quantum dots with ferromagnetic leads in the Kondo regime
• Quantum phase transition in a two-channel-Kondo quantum dot device
• Density matrix numerical renormalization group for non-Abelian symmetries
• Kondo effect in a semiconductor quantum dot coupled to ferromagnetic electrodes
• Nonequilibrium Kondo Effect in a Quantum Dot Coupled to Ferromagnetic Leads
• Kondo effect with non collinear polarized leads: a numerical renormalization group analysis
• Dynamical conductance in the two-channel Kondo regime of a double dot system
• Enhancement of the Two-channel Kondo Effect in Single-Electron boxes

Cited by in corpus (4)

• The Influence of Magnetic Anisotropy on the Kondo Effect and Spin-Polarized Transport through Magnetic Molecules, Adatoms and Quantum Dots
• Coulomb oscillations of the Fano-Kondo effect and zero bias anomalies in the double dot meso-transistor
• Study of couplings effect on the performance of a spin-current diode: Nonequilibrium Green's function based model
• Influence of spin-flip on the performance of the spin-diode