Enhanced noise at high bias in atomic-scale Au break junctions

Area of Science:

• Condensed matter physics
• Nanoscale science
• Experimental physics

Background:

• Heating in nanoscale systems is crucial for technology but challenging to measure.
• Previous studies focused on ionic heating, neglecting electronic heating in nanoscale junctions.

Purpose of the Study:

• To investigate electronic heating in atomic-scale gold break junctions.
• To use bias-driven current noise as a probe for electronic distribution.

Main Methods:

• Utilized atomic-scale gold break junctions.
• Measured bias-driven current noise to probe electronic distribution.
• Analyzed noise power dependence on applied bias.

Main Results:

• At low biases (<150 mV), noise matched shot noise expectations for a fixed electronic temperature.
• At higher biases, a nonlinear increase in noise power was observed.
• Flicker noise and bulk electrode heating were quantitatively ruled out as primary causes.

Conclusions:

• The observed nonlinear noise suggests localized electronic heating effects within the junction.
• Further experiments are needed to distinguish between vibrational and electron interaction mechanisms.
• Findings have implications for understanding and controlling heat in nanoscale electronic devices.