title: Length dependence of conductance in aromatic single-molecule junctions.
abstract: Using a scattering-state approach incorporating self-energy corrections to the junction level alignment, the conductance G of oligophenyldiamine-Au junctions is calculated and elucidated. In agreement with experiment, we find G decays exponentially with the number of phenyls with decay constant beta = 1.7. A straightforward, parameter-free self-energy correction, including electronic exchange and correlations beyond density functional theory (DFT), is found to be essential for understanding the measured values of both G and beta. Importantly, our results confirm quantitatively the picture of off-resonant tunneling in these systems and show that exchange and correlation effects absent from standard DFT calculations contribute significantly to beta.
authors.affiliation: Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Su Ying
authors.initials: SY
authors.lastname: Quek
authors.forename: Hyoung Joon
authors.initials: HJ
authors.lastname: Choi
authors.forename: Steven G
authors.initials: SG
authors.lastname: Louie
authors.forename: J B
authors.initials: JB
authors.lastname: Neaton