Nonlinear transport through a finite Hubbard chain connected to the electrodes

Coherent electronic transport through a molecular device is studied using non-equilibrium Green's function formalism. Such device is made of a short linear wire which is connected to para- and ferromagnetic electrodes. Molecule itself is described with the help of Hückel (tight-binding) model with the electron interactions treated within Hubbard approach, while the coupling to the electrodes is modeled through the use of a broad-band theory. Coulomb interactions within molecular wire are treated by means of the Hartree-Fock (HF) approximation. In the case of asymmetric coupling to paramagnetic electrodes, charging-induced rectification effect in biased molecular devices is discussed as a consequence of Coulomb repulsion. For the system with ferromagnetic electrodes, a significant magnetoresistance (MR) is predicted and its oscillations generated by Coulomb interactions are considered.