Electronic transmission of three-terminal pyrene molecular bridge

This paper investigates theoretically the electronic transmissionspectra of the three terminal pyrene molecular bridge and thequantum current distribution on each bond by the tight-binding modelbased on nonequilibrium Green's function and the quantum currentdensity approach, in which one π molecular orbital is takeninto account per carbon atom when the energy levels and HOMO-LUMOgap are obtained. The transmission spectra show that the electronictransmission of the three terminal pyrene molecular bridge dependsobviously on the incident electronic energy and the pyreneeigenenergy. The symmetrical and oscillation properties of thetransmission spectra are illustrated. A novel plus-minus energyswitching function is found. The quantum current distribution showsthat the loop currents inside the pyrene are induced, and some bondcurrents are much larger than the input and the output currents. Thereasons why the loop currents and the larger bond currents areinduced are the phase difference of the atomic orbits and thedegeneracy of the molecular orbits. The calculations illustrate thatthe quantum current distributions are in good agreement withKirchhoff quantum current conservation law.