Controlled electronic transport through branched molecular conductors

The conductance through a branched conductor placed between two electrodes is analyzed using the Landauer transport formulation within the framework of the single electron, and the tight binding approximations. Terminal side chains are expressed as self energy terms which map the branched conductor onto an effective linear chain Hamiltonian. The effect of uniform side branches on resonant zero-bias conductance is shown to be analytically solvable and particularly simple, where subtraction or addition of a single terminal site can induce an effective discontinuity in the main linear chain or can effectively decouple the side branch from the conductor. Manipulating the effective length of a side branch by a local terminal gate potential, control of the small bias current through the branched conductor is demonstrated.