Resistance-voltage dependence of nanojunctions during electromigration in ultrahigh vacuum
| Autor: | Hilbert von Löhneysen, T. Tomanic, Michael Marz, Roland Schäfer, Regina Hoffmann-Vogel, Birgit Kießig, D. Stöffler |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics FOS: Physical sciences Nanotechnology 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electromigration Thermal expansion Electronic Optical and Magnetic Materials Field electron emission Electrical resistance and conductance Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences 010306 general physics 0210 nano-technology Joule heating Ohmic contact Quantum tunnelling Voltage |
| Zdroj: | Physical Review B. 90 |
| ISSN: | 1550-235X 1098-0121 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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