Spin-flip effects on the supercurrent through mesoscopic superconducting junctions

We investigate the spin-flip effects on the Andreev bound states and the supercurrent in a superconductor/quantum-dot/superconductor system, theoretically. The spin-flip scattering in the quantum dot can reverse the supercurrent flowing through the system, which results in a π-junction transition. By controlling the energy level of the quantum dot, the π-junction transition can be caused to occur again. The two mechanisms of the π-junction transitions are interpreted within the picture of Andreev bound states.