Current-conserving Aharonov-Bohm interferometry with arbitrary spin interactions.

We propose a general scattering-matrix formalism that guarantees the charge conservation at junctions between conducting arms with arbitrary spin interactions. By using our formalism, we find that the spin-flip scattering can happen even at nonmagnetic junctions if the spin eigenstates in arms are not orthogonal, which has been missed in previous similar studies. We apply our formalism to the Aharonov-Bohm interferometer consisting of an n-type semiconductor ring with both the Rashba spin-orbit coupling and the Zeeman splitting. We discuss the characteristics of the interferometer as a conditional (unconditional) spin switch in the weak (strong) -coupling limit. [ABSTRACT FROM AUTHOR]