Andreev reflection with spin-flip scattering through a T-shaped double quantum dot

Abstract

The spin-dependent Andreev reflection (AR) tunneling through a ferromagnet double-quantum-dot superconductor (F-DQD-S) is studied using the nonequilibrium Green's function method. The F-DQD-S is a T-shaped hybrid structure where one of the dots is coupled to the F and S electrodes and the other dot is coupled to the first dot only. On each dot the intradot spin-flip process is present. The behavior of the F-DQD-S tunneling conductance is determined by the competition among the interdot coupling, the intradot spin-flip process, and the coupling of the first dot to the electrodes. When the interdot coupling is present, the quantum interference effects between the two dots cause secondary peaks in the tunneling conductance besides the primary one, indicating a structure in the AR spectrum. On the other hand, the spin-flip scattering process suppresses the AR peaks. With the spin-flip scattering strength increasing, the resonance peaks are split. (c) 2007 American Institute of Physics.