Conductance-Voltage Characteristics of Single Molecule Junction: in Resonant Tunneling Regime
Abstract
Electronic transport characteristics through a single molecule junction are investigated by using the Keldysh non equilibrium Green function (NEGF) model. The model consists of a molecular bridge (represented by a molecular orbital) attached with two free electron reservoirs (represents two metallic leads) and it is coupled with a vibrational degree of freedom (represents a molecular vibrational mode). The behavior of the electronic transfer through the molecular junction becomes more clearly visible by studying of the conductance-voltage characteristics. The numerical calculations are done based on this model to study the changes in conductance behavior through a single molecule junction in the resonant tunneling regime. According to our results, the conductance-voltage characteristics are influenced by (I) the electron-vibration interaction, (II) the molecular bridge-leads coupling strength, (III) the junction temperature, and (IV) the molecular vibrational mode energy. We conclude that the previous parameters have a significant role in determination of the electron conduction through the single-molecule junctions. Especially, the conductance is very sensitive to the molecular bridge-leads coupling strength and the junction temperature. These features provide important information about the study of the electronic transport phenomena in molecular junctions.
Keywords
Molecular junction, nonequilibrium Green function theory, electronic transport, conductance, electron-vibration coupling.Metrics