Nonequilibrium electron transport in strongly correlated molecular junctions

We investigate minimal molecular junction models to account for zero-bias anomaly and the inelastic transport by discrete molecular phonons. Nonlinear transport calculations with the imaginary-time nonequilibrium formalism shows that (highest-occupied-molecular-orbital)--(lowest-unoccupied-molecular-orbital) model with Anderson-Holstein interaction produces significant cotunneling conductance peaks in the vicinity of Kondo resonance, mediated by many-body resonance assisted by phonons at bias equal to the phonon frequency. Destruction of the resonance leads to negative-differential resistance in the sequential tunneling regime.