Positive current noise cross correlations in capacitively coupled double quantum dots with ferromagnetic leads

We examine cross correlations (CCs) in the tunneling currents through two parallel interacting quantum dots coupled to four independent ferromagnetic electrodes. We find that when either one of the two circuits is in the parallel configuration with sufficiently strong polarization strength, a mechanism of dynamical spin blockade, i.e., a spin-dependent bunching of tunneling events, governs transport through the system together with the interdot Coulomb interaction, leading to a sign reversal of the zero-frequency current CC in the dynamical channel blockade regime, and to enhancement of positive current CC in the dynamical channel antiblockade regimes, in contrast to the corresponding results for the case of paramagnetic leads.