Quantum Interference Beyond Single-Molecule Transport

Over the last ten years, there has been a growing interest in quantum interference effects observed in molecules. Remarkably, given their fragility in mesoscopic physics, quantum interference effects can be readily observed in molecules at room temperature in solution. This robustness comes from the extremely small size of the molecular components (1-2nm) and thereby the small dimensions over which phase coherence is required. In this talk I outline our efforts to explore molecular quantum interference effects beyond single molecules and to use these effects for more than simply switching current on/off.<br/>Firstly, I will outline our efforts to understand quantum interference beyond single molecules by studying clusters of molecules and monolayers of varying density. These studies indicate that current suppression at low bias due to destructive quantum interference may be either more or less pronounced for the same molecule, depending on whether the measurement is made on a single molecule or a monolayer. <br/>Secondly, I will outline our efforts exploring the potential for molecules exhibiting destructive quantum interference effects to be employed as dielectric materials, for example as gate dielectrics in organic transistors. Our initial studies show that it is possible to increase the dielectric constant of the monolayer, while maintaining low levels of current, but challenges remain in developing chemical insight as to how best to tune these properties.