Length dependence of conductance in aromatic single-molecule junctions.
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.
Quek
Su Ying
SY
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Choi
Hyoung Joon
HJ
Louie
Steven G
SG
Neaton
J B
JB