Coherent electron transport in hydrocarbon molecular devices

Electron transport is studied in a molecular device based on hydrocarbon polymeric chains connected to semi-infinite three-dimensional leads. The molecules are described using a tight binding model, taking into account carbon 2s and 2p, as well as hydrogen 1s-orbitals in two-center approximation. The leads are represented within the one-orbital tight binding model with the nearest neighbors hopping and simple cubic structure. An electron transmission in the device is calculated with the help of a transfer matrix method. It is shown that the transmission depends considerably on the geometry and the strength of the bonding of the molecule to the surface of the leads.