Coherent electron injection amd transport in molecular wires: inelastic tunneling and electron-phonon interactions

We review coherent transport mechanisms for a single charge carrier tunneling through one-dimensional molecular wires in the presence of electron-lattice coupling. We show that carrier injection at the metal/molecule interface and carrier propagation across the entire molecule both induce strong lattice distortions in the molecule. In the limit of low temperatures, the transport in such systems is mediated via the coherent propagation of composite entities such as polarons and solitons. The formation and propagation of such entities lead to different transport properties compared to the case of elastic scattering through a frozen molecular lattice. Finally, we briefly discuss open issues concerning transport at finite temperatures, competition between coherent and incoherent processes, and electronic correlations. (C) 2002 Published by Elsevier Science B.V.