Abstract
Electron tunneling through a molecular wire is studied as a function of the length and chemical structure of the molecule. The current intensity is calculated using the electron-scattering quantum-chemistry technique, the wire being connected at both ends to a planar metal-vacuum-metal nanojunction. The tunnel channels and the stepped characteristics are discussed in detail for the oligo (thiophene ethynylene) molecular wire. At low bias voltage, the conductance of a metal-molecular wire-metal junction follows a law with the interelectrode separation. The inverse damping length depends on the internal wire electronic structure and the contact conductance on the electrode-wire end interactions. Both and can be optimized by changing the chemical structure of the wire, and are given for a large number of oligomers.
- Received 10 March 1997
DOI:https://doi.org/10.1103/PhysRevB.56.4722
©1997 American Physical Society