Year: 2005
Type: article
Abstract: We have studied the instability of noble metal contacts under high biases (currents) by measuring their break conductance, a conductance just prior to the contact break. At high contact currents $(\ensuremath{\gtrsim}1\phantom{\rule{0.3em}{0ex}}\mathrm{mA})$, the break conductance distribution shows a broad single peak located at $\ensuremath{\sim}(10\text{--}50){G}_{0}$ (${G}_{0}\ensuremath{\equiv}2{e}^{2}∕h$ is the quantum unit of conductance). From the observed peak shift with the contact current, we showed that the contact break of noble metals most likely takes place when the contact current density reaches a critical value $(6\text{--}9)\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.3em}{0ex}}\mathrm{A}∕{\mathrm{cm}}^{2}$. Noble metal contacts thus make a current-induced break under high currents. At lower biases (currents), a contact tends to break off at one of its preferred contact geometries. We found that the $1{G}_{0}$ contact is always strongly preferred at the contact break of Au, while contacts of $1{G}_{0},\phantom{\rule{0.3em}{0ex}}2.5{G}_{0},\phantom{\rule{0.3em}{0ex}}5{G}_{0}$, and $7.5{G}_{0}$ appear at the break of Ag and Cu contacts. Preference of these contact geometries of Ag and Cu at the contact break is weakly affected by the contact bias (current).
Source: Physical Review B
Institution: Kyoto University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1978349876