2020/05/13 by Alireza Saffarzadeh, George Kirczenow
Chemistry · Engineering · Physics and Astronomy · #Break junction #Conductance #Copper #Electrical resistivity and conductivity #Electrochemical Analysis and Applications #Electrode #Hydrogen #Jump #Molecular Junctions and Nanostructures #Molecule #Nanomaterials and Printing Technologies #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevmaterials.4.056004
published in Physical Review Materials 4(5) (American Physical Society) · 8 pages, 4 figures
openalex publication_date 2020/05/13 · arxiv created 2020/05/16 · arxiv updated 2020/05/19 · openalex created_date 2020/05/21 · openalex updated_date 2026/08/05
The interplay between groups of water molecules and single-atom contacts, as reflected in the electrical conductances and mechanical forces of copper atomic junctions, is explored by means of first-principles theory and semiempirical calculations. We study the influence of the atomic geometries of copper electrodes with pyramidal and noncrystalline structures in the presence and absence of water on the conductance profiles as the electrodes approach each other. It is shown that the atomic arrangements of nanocontacts have crucial effects on the formation of plateaus and the conductance values. Groups of hydrogen bonded water molecules bridge the junction electrodes before a direct Cu-Cu contact between the electrodes is made. However, the bridging of the two copper electrodes by a single H2O molecule only occurs in the junctions with pyramidal electrodes. Our findings reveal that the presence of H2O molecules modifies strongly the conductance profile of these junctions. In the absence of water molecules, the pyramidal junctions exhibit continuous transitions between integer conductance plateaus, while in the presence of H2O molecules, these junctions show abrupt jump to contact behavior and no well-defined conductance plateaus. By contrast, in the absence of H2O molecules, the noncrystalline junctions display jump to contact behavior and no well-defined plateaus, while in the presence of H2O molecules they exhibit a jump to contact and abrupt transitions between fractional and integer plateaus.