Aharonov-Bohm oscillations and spin-polarized transport in a mesoscopic ring with a magnetic impurity - art. no. 075320

We present a detailed analysis of Aharonov-Bohm (AB) interference oscillati ons manifested through transmission of an electron in a mesoscopic ring wit h a magnetic impurity atom inserted in one of its arms. Spin-polarized tran sport is also studied. The electron interacts with the impurity through exc hange interaction, leading to spin-flip scattering. Transmission in the spi n-flipped and -unflipped channels are explicitly calculated. We show that e ntanglement between electron and spin-flipper states leads to reduction of AB oscillations in spite of the absence of any inelastic scattering. The sp in conductance (related to spin-polarized transmission coefficient) is asym metric under flux reversal, as opposed to the two-probe conductance, which is symmetric. We point out certain limitations of this model in regard to t he general notion of dephasing in quantum mechanics.