We study the effect of electron-vibron interactions on the inelastic transport properties of single-molecule nanojunctions. We use the nonequilibrium Green's functions technique and a model Hamiltonian to calculate the effects of second-order diagrams [double-exchange (DX) and dressed-phonon (DPH) diagrams] on the electron-vibration interaction and consider their effects across the full range of parameter space. The DX diagram, corresponding to a vertex correction, introduces an effective dynamical renormalization of the electron-vibron coupling in both the purely inelastic and the inelastic-resonant features of the inelastic electron tunneling spectrum. The purely inelastic features correspond to an applied bias around the energy of a vibron, while the inelastic-resonant features correspond to peaks (resonance) in the conductance. The DPH diagram affects only the inelastic resonant features. We also discuss the circumstances in which the second-order diagrams may be approximated in the study of more complex model systems.
|Number of pages||9|
|Journal||Physical Review B|
|Publication status||Published - 29 Aug 2011|
- CURRENT-VOLTAGE CHARACTERISTICS
- TUNNELING SPECTROSCOPY
- MOLECULAR JUNCTIONS