Elastic and inelastic electron tunneling in doped gold wire nanojunctions

Control and design of thermodynamically stable nanojunctions constitute to pose major challenges in realizing truly nanoelectronic devices as complex hybridization of atomic orbitals, especially at the junction edges, often determines the tunability of electronic conductance along with its thermopower. Using first-principles nonequilibrium analysis, we probe here how the doping of transition metal ions may control the charge transport in Au-chain nanojunctions. We find that electronic conductance of a pure gold-chain break junction is reduced considerably once it is thiolated on either side of the contact regions. Additional doping of Ni or Co ions, however, try to compensate it by yielding lower junction resistance while Mn ions behave differently as selective dopant. Onset of phonon modes further shed light on how the inelastic electron tunneling spectra can sense the chemical signature of various doped nanojunctions.