The Kondo and Fano Effects in Triple Quantum Dots Coupled to Noncollinear Ferromagnetic Leads

We use the equation-of-motion technique and non-equilibrium Green's function theory to study the Kondo effect and the Fano effect in triple quantum dots (QDs) coupled to symmetrically ferromagnetic leads whose magnetic moments are noncollinear. We address the question of how the noncollinear ferromagnetic leads influence the Kondo effect and how the side-coupled QDs present Fano interference. The results show that the spin splitting of the density of state (DOS) takes place in an intermediate direction between the magnetic moments in the two leads. When interdot coupling strength t_i is nonzero, Fano interference begins to play a major role in complicating the DOS of QD₀.