First Principles Description of Inelastic Scattering in Molecular Conductors

The intense investigations of molecular devices, as an alternative to standard electronics components, underlines the need to model the conduction mechanisms of nano-scale conductors. In addition to measurements of the elastic conductance through point-contacts, atomic-wires and molecules, recent experiments have shown inelastic tunneling currents through, for example, a hydrogen molecule attached to platinum contacts [1], atomic gold wires [2] and alkanedithiol molecules [3]. In this work we calculate the inelastic conductance of these three systems, using an ab-initio (DFT) method and/or simpler models to describe the systems. The conductance is calculated by solving the Non Equilibrium Greens Function (NEGF) equations. We have also developed an approximate treatment that both simplifies the calculations dramatically and allows for transparent interpretations of the results.