title: Controlling the formation process and atomic structures of single pyrazine molecular junction by tuning the strength of the metal-molecule interaction.
abstract: The formation process and atomic structures were investigated for single pyrazine molecular junctions sandwiched by three different Au, Ag, and Cu electrodes using a mechanically controllable break junction technique in ultrahigh vacuum conditions at 300 K. We demonstrated that the formation process of the single-molecule junction crucially depended on the choice of the metal electrodes. While single-molecule junction showing two distinct conductance states were found for the Au electrodes, only the single conductance state was evident for the Ag electrodes, and there was no junction formation for the Cu electrodes. These results suggested that metal-molecule interaction dominates the formation process and probability of the single-molecule junction. In addition to the metal-molecule interaction, temperature affected the formation process of the single-molecule junction. The single pyrazine molecular junction formed between Au electrodes exhibited significant temperature dependence where the junction-formation probability was about 8% at 300 K, while there was no junction-formation at 100 K. Instead of the junction formation, an Au atomic wire was formed at the low temperature. This study provides insight into the tuning of the junction-forming process for single-molecule junctions, which is needed to construct device structures on a single molecule scale.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551, Japan. kiguti@chem.titech.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kaneko
authors.forename: Ryoji
authors.initials: R
authors.lastname: Takahashi
authors.forename: Shintaro
authors.initials: S
authors.lastname: Fujii
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nishino
authors.forename: Manabu
authors.initials: M
authors.lastname: Kiguchi