Electrical conductance and structure of copper atomic junctions in the presence of water molecules

Abstract

We have investigated Cu atomic contacts in the presence of H₂O both experimentally and theoretically. The conductance measurements showed the formation of H₂O/Cu junctions with a fixed conductance value of around 0.1 G₀ (G₀ = 2e²/h). These structures were found to be stable and could be stretched over 0.5 nm, indicating the formation of an atomic or molecular chain. In agreement with the experimental findings, theoretical calculations revealed that the conductance of H₂O/Cu junctions decreases in stages as the junction is stretched, with the formation of a H₂O/Cu atomic chain with a conductance of ca. 0.1 G₀ prior to junction rupture. Conversely, in the absence of H₂O, the conductance of the Cu junction remains close to 1 G₀ prior to the junction rupture and abrupt conductance drop.