title: Single molecule electronics: increasing dynamic range and switching speed using cross-conjugated species.
abstract: Molecular electronics is partly driven by the goal of producing active electronic elements that rival the performance of their solid-state counterparts, but on a much smaller size scale. We investigate what constitutes an ideal switch or molecular device, and how it can be designed, by analyzing transmission plots. The interference features in cross-conjugated molecules provide a large dynamic range in electron transmission probability, opening a new area for addressing electronic functionality in molecules. This large dynamic range is accessible through changes in electron density alone, enabling fast and stable switching. Using cross-conjugated molecules, we show how the width, depth, and energetic location of the interference features can be controlled. In an example of a single molecule transistor, we calculate a change in conductance of 8 orders of magnitude with an applied gate voltage. Using multiple interference features, we propose and calculate the current/voltage behavior of a molecular rectifier with a rectification ratio of >150,000. We calculate a purely electronic negative differential resistance behavior, suggesting that the large dynamic range in electron transmission probability caused by quantum interference could be exploited in future electronic devices.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA. dqandrews@u.northwestern.edu
authors.forename: David Q
authors.initials: DQ
authors.lastname: Andrews
authors.forename: Gemma C
authors.initials: GC
authors.lastname: Solomon
authors.forename: Richard P
authors.initials: RP
authors.lastname: Van Duyne
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ratner