Controlling charge transport in single molecules
Charge transport in molecular systems, including DNA, is related to many basic chemical and biological processes, and also critical to energy conversion and electronic device applications with molecules. This important phenomenon is often described as either coherent tunneling over a short distance or incoherent hopping over a long distance. Here we show evidence of an intermediate regime where coherent and incoherent processes coexist in double helical DNA. In addition to basic charge transport mechanism, we also discuss the electromechanical and thermoelectric properties of single DNA molecules. These properties are analogous to piezoresistivity and thermoelectricity in bulk materials, which have many real world applications. Our study shows that to understand charge transport in molecules, one must study the interplays between electrical, thermal and mechanical properties of single molecules.