  A circularly polarized laser pulse can induce persistent intra-molecular
currents by either exciting or ionizing molecules. These two cases are
identified as electron currents and hole currents, respectively, and up to now
they have been studied only separately. We report \textit{ab initio}
time-dependent density-functional theory (TDDFT) simulations of currents during
resonance-enhanced two-photon ionization of benzene, which reveal for the first
time that both electron and hole currents can be present simultaneously. By
adjusting the intensity of the laser pulse, the balance between the two types
of current can be controlled, and the overall sign of the current can be
switched. We provide a physical explanation for the effect in terms of complex
molecular orbitals which is consistent with the TDDFT simulations.
