2003/02/19 by Bing Dong, H. L. Cui, H L Cui +4
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1088/0953-8984/15/49/019
published as Published in J. Phys.: Cond. Matter 15, 8435 (2003) · 8 pages, 5 figures
arxiv created 2003/02/19 · openalex publication_date 2003/11/25 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We investigate the equilibrium and out-of-equilibrium Kondo effects in a single-level interacting quantum dot connected to two ferromagnetic leads. Within the noncrossing approximation, we calculate the total density of states (DOS), the linear conductance and the nonlinear differential conductance for both the parallel and the antiparallel alignments of the spin polarization orientation in the leads, followed by a brief discussion regarding the validity of this approach. Numerical calculations show that, for the antiparallel alignment, a single Kondo peak always appears in the equilibrium DOS, resulting in conventional temperature behaviour in the linear conductance and the zero-bias maximum in the differential conductance. The strength of the DOS peak is gradually suppressed with increasing polarization, due to the fact that formation of the Kondo-correlated state is more difficult in the presence of higher polarization. In contrast, for the parallel configuration the Kondo peak in the DOS descends precipitately and splits into two peaks to form a very steep valley between them. This splitting contributes to the appearance of a 'hump' in the temperature-dependent linear conductance and a nonzero-bias maximum in the differential conductance. Moreover, application of a bias voltage can split each Kondo peak into two in the nonequilibrium DOS for both configurations. Finally we point out that the tunnel magnetoresistance could be an effective tool to demonstrate the different Kondo effects in the different spin configurations found here.