title: Shot Noise of 1,4-Benzenedithiol Single-Molecule Junctions.
abstract: We report measurements of the shot noise on single-molecule Au-1,4-benzenedithiol-Au junctions, fabricated with the mechanically controllable break junction (MCBJ) technique at 4.2 K in a wide range of conductance values from 10(-2) to 0.24 conductance quanta. We introduce a simple measurement scheme using a current amplifier and a spectrum analyzer and that does not imply special requirements regarding the electrical leads. The experimental findings provide evidence that the current is carried by a single conduction channel throughout the whole conductance range. This observation suggests that the number of channels is limited by the Au-thiol bonds and that contributions due to direct tunneling from the Au to the π-system of the aromatic ring are negligible also for high conductance. The results are supported by quantum transport calculations using density functional theory.
authors: Department of Physics, University of Konstanz , 78457 Konstanz, Germany.
authors: M A
authors: MA
authors: Karimi
authors: Department of Physics, University of Konstanz , 78457 Konstanz, Germany.
authors: S G
authors: SG
authors: Bahoosh
authors: Department of Physics, University of Konstanz , 78457 Konstanz, Germany.
authors: M
authors: M
authors: Herz
authors: Department of Physics, University of Konstanz , 78457 Konstanz, Germany.|International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan.
authors: R
authors: R
authors: Hayakawa
authors: Department of Physics, University of Konstanz , 78457 Konstanz, Germany.
authors: F
authors: F
authors: Pauly
authors: Department of Physics, University of Konstanz , 78457 Konstanz, Germany.
authors: E
authors: E
authors: Scheer
keywords: Single-molecule junction; charge transport; density functional theory; inelastic electron tunneling spectroscopy; low temperature; shot noise