Abstract
We present first-principles calculations of the characteristics of an molecule sandwiched between Au and Pt electrodes in the presence of electron-phonon interactions. The conductance is found to decrease by a few percentages at threshold voltages corresponding to the excitation energy of longitudinal vibrations of the molecule. In the case of Pt electrodes, the transverse vibrations can mediate transport through otherwise nontransmitting channels leading to an increase in the differential conductance even though the hydrogen junction is characterized predominately by a single almost fully open transport channel. In the case of Au, the transverse modes do not affect the because the states are too far below the Fermi level. A simple explanation of the first-principles results is given using scattering theory. Finally, we compare and discuss our results in relation to experimental data.
- Received 11 March 2009
DOI:https://doi.org/10.1103/PhysRevB.79.235411
©2009 American Physical Society