Angular conductance resonances of quantum dots non-collinearly coupled to ferromagnetic leadsJ. Fransson
Department of Materials Science and Engineering, Royal Institute of Technology (KTH) SE-100 44 Stockholm, Sweden and Physics Department, Uppsala University - Box 530, SE-751 21 Uppsala, Sweden and NORDITA - Blegdamsvej 17, DK-2100 Copenhagen, Denmark
received 22 February 2005; accepted in final form 22 April 2005
published online 13 May 2005
The zero-bias conductance of quantum dots coupled to ferromagnetic leads is investigated. In the strong-coupling regime, it is found that the conductance is a non-monotonic function of the angle between the magnetisation directions in the two contacts. This behaviour is an effect of the presence of the leads which induces an angle-dependent spin-split of the quantum dot states, and spin-flip transitions between the quantum dot states whenever the magnetisation directions of the leads are non-collinear, which enhances the current density at the chemical potential. In the weak-coupling regime, the system reverts to normal spin valve character.
72.25.Mk - Spin transport through interfaces.
73.63.Kv - Quantum dots.
73.23.Hk - Coulomb blockade; single-electron tunneling.
© EDP Sciences 2005