Cotunneling through a magnetic quantum dot coupled to ferromagnetic leads with noncollinear magnetizations

摘要

By means of the second-order perturbation theory, we analyze theoretically spin-dependent electronic transport through a singly occupied quantum dot in the cotunneling regime. The system is described by the impurity Anderson Hamiltonian with arbitrary Coulomb correlation parameter U. The dot is coupled to two ferromagnetic leads whose magnetic moments are noncollinear. It is also assumed that the dot level is intrinsically spin-split due to an effective molecular field. It is shown that the tunnel magnetoresistance strongly depends on the angle between the leads' magnetizations. (c) 2006 Elsevier B.V. All rights reserved.