title: Engineering nanometre-scale coherence in soft matter.
abstract: Electronic delocalization in redox-active polymers may be disrupted by the heterogeneity of the environment that surrounds each monomer. When the differences in monomer redox-potential induced by the environment are small (as compared with the monomer-monomer electronic interactions), delocalization persists. Here we show that guanine (G) runs in double-stranded DNA support delocalization over 4-5 guanine bases. The weak interaction between delocalized G blocks on opposite DNA strands is known to support partially coherent long-range charge transport. The molecular-resolution model developed here finds that the coherence among these G blocks follows an even-odd orbital-symmetry rule and predicts that weakening the interaction between G blocks exaggerates the resistance oscillations. These findings indicate how sequence can be exploited to change the balance between coherent and incoherent transport. The predictions are tested and confirmed using break-junction experiments. Thus, tailored orbital symmetry and structural fluctuations may be used to produce coherent transport with a length scale of multiple nanometres in soft-matter assemblies, a length scale comparable to that of small proteins.
authors.affiliation: Departments of Chemistry, Biochemistry and Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Chaoren
authors.initials: C
authors.lastname: Liu
authors.affiliation: Center of Biosensor &Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Limin
authors.initials: L
authors.lastname: Xiang
authors.affiliation: Departments of Chemistry, Biochemistry and Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Departments of Chemistry, Biochemistry and Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Departments of Chemistry, Biochemistry and Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: David N
authors.initials: DN
authors.lastname: Beratan
authors.affiliation: Center of Biosensor &Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Yueqi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Center of Biosensor &Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Nongjian
authors.initials: N
authors.lastname: Tao
mesh_terms: D004247:DNA / Q000737:chemistry*; D004553:Electric Conductivity; D004583:Electrons; D006147:Guanine / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D011789:Quantum Theory
chemical_list: D006147:Guanine; D004247:DNA