Spin-polarized electronic transport through a quantum dot: non-colinear magnetic configuration

Tunnel magnetoresistance in a double-barrier junction with ferromagnetic electrodes and a single-level quantum dot as the central part is analyzed theoretically in the sequential tunneling regime. The considerations apply to arbitrary configuration of the magnetic moments of the two external electrodes, and are valid in the limit of strong Coulomb correlation on the dot. Electric current and tunnel magnetoresistance are calculated for both symmetric and non-symmetric situations. In the latter case, transport characteristics display typical diode-like features. It is shown, however, that the diode-like behavior of the system is efficient only in the colinear configurations, whereas it is strongly suppressed when magnetic moments of the electrodes are non-colinear.