title: Intermediate tunnelling-hopping regime in DNA charge transport.
abstract: Charge transport in molecular systems, including DNA, is involved in many basic chemical and biological processes, and its understanding is critical if they are to be used in electronic devices. This important phenomenon is often described as either coherent tunnelling 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-stranded DNA. We measure charge transport in single DNA molecules bridged to two electrodes as a function of DNA sequence and length. In general, the resistance of DNA increases linearly with length, as expected for incoherent hopping. However, for DNA sequences with stacked guanine-cytosine (GC) base pairs, a periodic oscillation is superimposed on the linear length dependence, indicating partial coherent transport. This result is supported by the finding of strong delocalization of the highest occupied molecular orbitals of GC by theoretical simulation and by modelling based on the Büttiker theory of partial coherent charge transport.
authors.affiliation: 1] Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA [2] Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Limin
authors.initials: L
authors.lastname: Xiang
authors.affiliation: 1] Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA [2] Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Julio L
authors.initials: JL
authors.lastname: Palma
authors.affiliation: Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Bruot
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Vladimiro
authors.initials: V
authors.lastname: Mujica
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ratner
authors.affiliation: 1] Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA [2] School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Nongjian
authors.initials: N
authors.lastname: Tao
mesh_terms: D020029:Base Pairing; D003596:Cytosine / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry; D009690:Nucleic Acid Conformation
chemical_list: D006147:Guanine; D003596:Cytosine; D004247:DNA