Ab initio analysis of electron currents through benzene, naphthalene, and anthracene nanojunctions

The current-voltage characteristics of benzene, naphthalene, and anthracene attached to three types of nanoelectrode conformations are calculated using a combined density functional theory and Green's functions approach, whereby the local chemistry and the extended physics of the problem are properly and fully incorporated. The selected molecules are important building units for a scenario of molecular devices to perform analog and logical operations. We find out that conductances are high and tunneling barriers are low when compared to saturated alkanes and unsaturated oligophenylene vinylenes. On the other hand, the conformation of the nanoelectrodes addressing the molecules has a strong effect on the current-voltage characteristics of the molecules. One of the studied conformations is able to eliminate the tunneling barrier by withdrawing electrons from the surface of the nanoelectrodes