title: Effects of the molecule-electrode interface on the low-bias conductance of Cu-H2-Cu single-molecule junctions.
abstract: The atomic structure and electronic transport properties of a single hydrogen molecule connected to both symmetric and asymmetric Cu electrodes are investigated by using the non-equilibrium Green's function formalism combined with the density functional theory. Our calculations show that in symmetric Cu-H2-Cu junctions, the low-bias conductance drops rapidly upon stretching, while asymmetric ones present a low-bias conductance spanning the 0.2-0.3 G0 interval for a wide range of electrode separations. This is in good agreement with experiments on Cu atomic contacts in a hydrogen environment. Furthermore, the distribution of the calculated vibrational energies of the two hydrogen atoms in the asymmetric Cu-H2-Cu junction is also consistent with experiments. These findings provide clear evidence for the formation of asymmetric Cu-H2-Cu molecular junctions in breaking Cu atomic contacts in the presence of hydrogen and are also helpful for the design of molecular devices with Cu electrodes.
authors.affiliation: Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China.
authors.forename: Zhuoling
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China.
authors.forename: Ziyong
authors.initials: Z
authors.lastname: Shen
authors.affiliation: School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Ireland.
authors.forename: Stefano
authors.initials: S
authors.lastname: Sanvito
authors.affiliation: Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China.
authors.forename: Shimin
authors.initials: S
authors.lastname: Hou