Effects of electrodes and nitrogen-atom locations on electron transport in C₅₉N molecular junctions: A first-principles study

The electron-transport properties of C₅₉N molecular junctions with different electrodes (Au, Al, and CNT) are investigated by density functional theory (DFT) combined with the first-principle nonequilibrium Green's function (NEGF). The current-voltage characteristics of all the models are calculated. The results show both electrode species and nitrogen-atom location may affect the transport properties of the C₅₉N molecular junction. When the nitrogen atom of the C₅₉N molecule is located close to one side of the junction, the rectifying behavior can be found in CNT-electrode models, while there is no observable rectification in metal-electrode models. The negative differential resistance may be observed in the C₅₉N molecular junction using CNT electrodes when the nitrogen atom is at a certain location. The results are discussed through examining the transmission spectra, the molecular projected self-consistent Hamiltonian states, and the projection of the density of states.