Cotunneling through quantum dots coupled to magnetic leads: Zero-bias anomaly for noncollinear magnetic configurations

摘要: Cotunneling transport through quantum dots weakly coupled to noncollinearly magnetized leads is analyzed theoretically by means of the real-time diagrammatic technique. The electric current, dot occupations, and spin are calculated in Coulomb blockade regime for arbitrary magnetic configuration system. It shown that an effective exchange field exerted on ferromagnetic can significantly modify characteristics noncollinear configurations, particular zero-bias anomaly found recently [I. Weymann et al., Phys. Rev. B 72, 113301 (2005)] antiparallel configuration. For asymmetric Anderson model, gives rise precession spin, which a nonmonotonic dependence differential conductance tunnel magnetoresistance angle between moments leads. An enhanced negative were certain configurations.