Nonequilibrium spintronic transport through Kondo impurities

Abstract

In this work we analyze the nonequilibrium transport through a quantum impurity (quantum dot or molecule) attached to ferromagnetic leads by using a hybrid numerical renormalization group-time-dependent density matrix renormalization group thermofield quench approach.For this, we study the bias dependence of the differential conductance through the system, which shows a finite zero-bias peak, characteristic of the Kondo resonance and reminiscent of the equilibrium local density of states. In the non-equilibrium settings, the resonance in the differential conductance is also found to decrease with increasing the lead spin polarization. The latter induces an effective exchange field that lifts the spin degeneracy of the dot level. Therefore as we demonstrate, the Kondo resonance can be restored by counteracting the exchange field with a finite external magnetic field applied to the system. Finally, we investigate the influence of temperature on the nonequilibrium conductance, focusing on the split Kondo resonance. Our work thus provides an accurate quantitative description of the spin-resolved transport properties relevant for quantum dots and molecules embedded in magnetic tunnel junctions.

10 pages, 8 figures

References in corpus (8)

• The density-matrix renormalization group in the age of matrix product states
• The numerical renormalization group method for quantum impurity systems
• 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
• Spin effects in single electron tunneling
• Kondo effect in a semiconductor quantum dot coupled to ferromagnetic electrodes
• Nonequilibrium Kondo Effect in a Quantum Dot Coupled to Ferromagnetic Leads

Cited by in corpus (5)

• Nonequilibrium Seebeck effect and thermoelectric efficiency of Kondo-correlated molecular junctions
• Simulations of the dynamics of quantum impurity problems with matrix product states
• Thermoelectric properties of a double quantum dot out of equilibrium in Kondo and intermediate valence regimes
• Role of asymmetry in thermoelectric properties of a double quantum dot out of equilibrium
• Transport in Single Quantum Dots: A Review from Linear Response to Nonlinear Regimes