Molecular conduction through adlayers: cooperative effects can help or hamper electron transport.
We use a one-electron, tight-binding model of a molecular adlayer sandwiched between two metal electrodes to explore how cooperative effects between molecular wires influence electron transport through the adlayer. When compared to an isolated molecular wire, an adlayer exhibits cooperative effects that generally enhance conduction away from an isolated wire's resonance and diminish conductance near such a resonance. We also find that the interwire distance (related to the adlayer density) is a key quantity. Substrate-mediated coupling induces most of the cooperative effects in dense adlayers, whereas direct, interwire coupling (if present) dominates in sparser adlayers. In this manner, cooperative effects through dense adlayers cannot be removed, suggesting an optimal adlayer density for maximizing conduction.
Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States. mgreuter@u.northwestern.edu
Matthew G
MG
Reuter
Tamar
T
Seideman
Mark A
MA
Ratner
D003198:Computer Simulation; D004553:Electric Conductivity; D004579:Electron Transport; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*