2014/09/04 by D. Stöffler, Michael Marz, M. Marz +7
Engineering · Physics and Astronomy · #Composite material #Condensed matter physics #Electrical engineering #Electromigration #Electron #Field electron emission #Force Microscopy Techniques and Applications #Joule heating #Materials science #Metal #Metallurgy #Molecular Junctions and Nanostructures #Nanoclusters #Nanotechnology #Ohmic contact #Optoelectronics #Physics #Quantum tunnelling #Surface and Thin Film Phenomena #Thermal #Thermodynamics #Voltage #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.90.115406
published as Phys. Rev. B 90, 115406 (2014)
openalex publication_date 2014/09/04 · arxiv created 2014/11/01 · arxiv updated 2014/11/04 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The electrical resistance R of metallic nanocontacts subjected to controlled cyclic electromigration in ultrahigh vacuum has been investigated in situ as a function of applied voltage V. For sufficiently small contacts, i.e., large resistance, a decrease of R(V) while increasing V is observed. This effect is tentatively attributed to the presence of contacts separated by thin vacuum barriers in parallel to ohmic nanocontacts. Simple model calculations indicate that both thermal activation or tunneling can lead to this unusual behavior. We describe our data by a tunneling model whose key parameter, i.e., the tunneling distance, changes because of thermal expansion due to Joule heating and/or electrostatic strain arising from the applied voltage. Oxygen exposure during electromigration prevents the formation of negative R(V) slopes, and at the same time enhances the probability of uncontrolled melting, while other gases show little effects. In addition, indication for field emission has been observed in some samples.