Many-neighbor treatment of molecular-switch transmission

We use the many-neighbor description of a monoatomic chain with a single impurity, characterized by long-range couplings, to study the electron transmission properties of a conducting polymer. The transmission probability is obtained by a method based on the Lippmann-Schwinger equation. Control of the switch operation is facilitated by the presence of a peak in the transmission probability at the impurity site energy for sufficiently weak impurity-chain coupling. We show that this peak becomes rather distorted, when long-range coupling is present in the chain, and provides a more convenient means of switch control.