Break Voltage of the 1G0 Contact of Noble Metals and Alloys

Abstract

We have measured the break voltage of the 1G0 contact of Au, Ag, Cu, and AuAg alloys at room temperature in ultrahigh vacuum. Exploiting the break junction technique, we produced a 1G0 contact and broke it by applying a voltage ramp. The break voltage of each metal exhibits a broad distribution, and the average break voltage decreases as Au > Cu & Ag, in consistent with the elemental dependence of the high-bias stability of the 1G0 contact suggested in previous experimental studies. In AuAg alloys, the break-voltage distribution for some alloys exhibits a double-peak structure, each peak locating close to the break voltage of the 1G0 contact of pure Au and Ag, respectively. This observation suggests that the break voltage of AuAg alloys is locally determined by the elemental species of the atom occupying the contact site.

Admittance of Atomic and Molecular Junctions and Their Signal Transmission

“…However, there have been a few experiments that employ modulated biases or fast bias ramps. For example, in the experiments exploring the current disruption of single-atom contacts [ 48 , 49 , 50 ], the bias voltage was ramped to a high value in a short time interval. The conductance of Au single-atom contacts was found unchanged during the bias ramp of ∼10 s [ 50 ], and this observation indirectly suggests that the electron transmission should be unaffected by the bias variation for frequencies up to ∼0.3 MHz.…”

“…For making the healing effect work, the frequency of bias modulation must exceed the thermal hopping frequency of contact atoms which increases to ∼1 MHz when the bias approaches the breakdown voltage [ 63 ]. Conventional current-disruption measurements [ 48 , 49 , 50 ] are difficult to perform at such high frequencies, and it remains an open question whether single-atom contacts are more stabilized under high-frequency biases. The answer to this question will become a critical issue when atom-sized interconnects transmit high-amplitude RF signals.…”

High-Bias Instability of Atomic and Molecular Junctions

“…4, and the contact heating becomes negligible at 1.2 V. In return for these advantages, the single-atom contacts become short-lived at room temperature, and we have to carry out fast measurements for determining their break voltage. Our procedures for measuring the break voltage of single-atom contacts are the following (Miura et al, 2009). First, a constant bias of 0.1 V is applied across a (contact)+R where R is a current-sensing resistor.…”

Effect of Bias Voltage on a Single-Molecule Junction Investigated by Surface-Enhanced Raman Scattering

“…1 V) is applied to a small gap (ca. 1 nm), the electric field can be larger than 10 9 V/m, and the single molecule is under a high electric field. , In order to study and utilize single-molecule junctions, it is critically important to understand the effect of the bias voltage on the single-molecule junctions.…”