Elastic and inelastic electron transport through alkane-based molecular junctions

Résumé

In this thesis the electronic and transport properties of alkane-based molecular junctions are addressed by means of density functional theory (DFT) in combination with the nonequilibrium Green's function (NEGF) formalism. The chemical nature of the anchoring groups and the local geometry of the metal/molecule interface are found to control the electrostatics of band alignment and thus to strongly in uence the conductance of the molecular junction. The inelastic tunneling spectra (IETS) of thiol-functionalized alkanes are calculated at different level of approximation and compared, providing at the same time useful guidance for computationally more efficient calculations. The calculated IETS is also used to unambiguously distinguish the highly conducting covalent Au-C bond of alkane chains to a gold surface from another binding scenario where a dimethyl-tin group is used. Finally, inelastic transport through a single electronic level weakly coupled to the leads is explored by means of the master equation approach.