Bound states in ab initio approaches to quantum transport: A time-dependent formulation

In this work we study the role of bound electrons in quantum transport. The partition-free approach by Cini is combined with time-dependent density functional theory (TDDFT) to calculate total currents and densities in interacting systems. We show that the biased electrode-device-electrode system with bound states does not evolve towards a steady regime. The density oscillates with history-dependent amplitudes and, as a consequence, the effective potential of TDDFT oscillates too. Such time dependence might open new conductive channels, an effect which is not accounted for in any steady-state approach and might deserve further investigations.