  The role of the discontinuity of the exchange-correlation potential of
density functional theory is studied in the context of electron transport and
shown to be intimately related to Coulomb blockade. By following the time
evolution of an interacting nanojunction attached to biased leads, we find
that, instead of evolving to a steady state, the system reaches a dynamical
state characterized by correlation-induced current oscillations. Our results
establish a dynamical picture of Coulomb blockade manifesting itself as a
periodic sequence of charging and discharging of the nanostructure.
