Manifestation of bound states and coupling to leads in coherent transmission through multiterminal molecular conductors

Abstract

We examine analytically a rarely if ever addressed issue: the effects of scattering at the conductor-lead interfaces on the transmittivity of N-terminal molecular conductors. The feeding leads are not one-dimensional and the strength of wire-lead coupling is allowed to be arbitrary. The conductor imbedded into a circuit is supposed to be a Y junction of three identical molecular wires or of two identical wires and one different wire. The wire connector is a C-H group and wires are conjugated and/or saturated oligo(hydro)carbons. The spectrum of branched oligo(hydro)carbons is rationalized in terms of extended and bound states. The junctions, where identical wires are equally coupled to the respective leads (all-symmetric junctions), are compared with hybrid junctions, where nonequivalence of terminal-to-terminal transmission appears due to either not identical wires or not equal coupling, or both. These model systems reveal incredible potentials of branched oligo(hydro)carbons for engineering a variety of molecular electronic devices. In addition, the role of wire connectors, atomic and molecular, is briefly discussed. Some of the obtained results are valid for N-terminal starlike junctions. © 2012 American Physical Society.