By means of the Keldysh-Green-function method, the electrochemical-potential variations across a constriction are analyzed. We discuss specifically the case of a one-dimensional chain joining two Bethe lattices of coordination 4. Our results show that the total conductance of the system and its local chemical potential variations depend dramatically on the interference between the chain transmittivity and the reflectivity at the reservoir-chain contact. We show a case in which, with a transmittivity less than one, a zero chemical-potential drop is found along the inner linear chain.

• Received 27 November 1989

DOI:https://doi.org/10.1103/PhysRevB.41.8553