We investigate models of molecular junctions which constitute minimal Hamiltonians to account for zero-bias-anomaly and the satellite features of inelastic transport by molecular phonons. Through nonlinear transport calculations with the imaginary-time nonequilibrium formalism, a HOMO-LUMO model with Anderson-Holstein interaction is shown to produce co-tunneling conductance peak in the vicinity of Kondo resonance which is mediated by a re-emergent many-body resonance assisted by phonon excitations at bias equal to the phonon frequency. Destruction of the resonance leads to negative-differential-resistance in the sequential tunneling regime.
Categories: cond-mat.str-el cond-mat.mes-hall