Coherent effects in magneto-transport through Zeeman split levels

We study non-equilibrium electronic transport through a quantum dot or impurity weakly coupled to ferromagnetic leads. Based on the rate equation formalism we derive noise spectra for the transport current. We show that due to quantum interference between different spin components of the current the spectrum develops a peak or a dip at the frequency corresponding to Zeeman splitting in the quantum dot. The detailed analysis of the spectral structure of the current is carried out for noninteracting electrons as well as in the regime of Coulomb blockade.