title: Benzenedithiol: a broad-range single-channel molecular conductor.
abstract: More than a decade after the first report of single-molecule conductance, it remains a challenging goal to prove the exact nature of the transport through single molecules, including the number of transport channels and the origin of these channels from a molecular orbital point of view. We demonstrate for the archetypical organic molecule, benzenedithiol (BDT), incorporated into a mechanically controllable break junction at low temperature, how this information can be deduced from studies of the elastic and inelastic current contributions. We are able to tune the molecular conformation and thus the transport properties by displacing the nanogap electrodes. We observe stable contacts with low conductance in the order of 10(-3) conductance quanta as well as with high conductance values above ∼0.5 quanta. Our observations show unambiguously that the conductance of BDT is carried by a single transport channel provided by the same molecular level, which is coupled to the metallic electrodes, through the whole conductance range. This makes BDT particularly interesting for applications as a broad range coherent molecular conductor with tunable conductance.
authors.affiliation: Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Youngsang
authors.initials: Y
authors.lastname: Kim
authors.forename: Torsten
authors.initials: T
authors.lastname: Pietsch
authors.forename: Artur
authors.initials: A
authors.lastname: Erbe
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Belzig
authors.forename: Elke
authors.initials: E
authors.lastname: Scheer
mesh_terms: D004553:Electric Conductivity; D004566:Electrodes; D004583:Electrons; D016252:Microscopy, Scanning Tunneling; D015233:Models, Statistical; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry; D011789:Quantum Theory; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: C516314:1,4-benzenedithiol; D009930:Organic Chemicals; D013438:Sulfhydryl Compounds