ARTICLE
Electrochemical Control of Stability and Restructuring Dynamics in AuⴚAgⴚAu and AuⴚCuⴚAu Bimetallic Atom-Scale Junctions Ping Shi and Paul W. Bohn* Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
ABSTRACT Metallic atom-scale junctions (ASJs) are interesting fundamentally because they support ballistic transport, characterized by conduction quantized in units of G0 ⴝ 2e2/h. They are also of potential practical interest since ASJ conductance is extraordinarily sensitive to molecular adsorption. Monometallic Au ASJs were previously fabricated electrochemically using an Iⴚ/I3ⴚ medium and a unique open working electrode configuration to produce slow electrodeposition or electrodissolution, resulting in reproducible ASJs with limiting conductance
sensitive to molecular adsorption, making them excellent candidates for highly sensitive chemical sensors.20⫺24 Given that these junctions are inherently atomic in size, it is not surprising that they exhibit interesting quantum phenomena, even at room temperature. The conductance is quantized by
