Quantum Interference and Josephson Effect in a Single Molecule Electronic System

The Josephson effect in a molecular structure mimicking a benzene molecule (C
₆
H
₆
) placed between two nanometric superconducting electrodes is theoretically studied. In the tight bindingmodel, the Bogoliubov-de Gennes equations are solved to derive the Andreev reflection coefficient and hence the dc Josephson current. Two effects are pointed out: the quantum interference effect on the supercurrent due to the presence of two branches in the molecule and a on-resonance off -resonance state operation in the presence of an applied gate voltage. The results provide an insight on the molecular electronics devices in the case of superconducting nano-electrodes.