Electronic Temperature and Two-Electron Processes in Overbias Plasmonic Emission from Tunnel Junctions

Area of Science:

• Condensed matter physics
• Materials science
• Nanotechnology

Background:

• Accurate electronic temperature determination is crucial for plasmon-enhanced catalysis and nanofabrication.
• Understanding electron-phonon coupling in nanostructures is key to controlling their properties.

Purpose of the Study:

• To demonstrate a novel method for measuring electronic temperatures in metallic nanostructures.
• To investigate the deviation between electronic and lattice temperatures at low temperatures.

Main Methods:

• Utilizing tunnel electroluminescence emission edge shape in tunnel plasmonic nanocavities.
• Analyzing the universal thermal distribution with bias voltage as chemical potential.

Main Results:

• Electronic temperature accurately measured by electroluminescence emission edge shape.
• Significant deviation between electronic and lattice temperatures observed below 30 K for currents > 15 nA.
• Deviation explained by a two-electron process exciting plasmon modes.

Conclusions:

• Tunnel electroluminescence provides a new method for determining electronic temperatures.
• The findings resolve long-standing controversies regarding overbias emission in tunnel junctions.
• This work offers insights into quasiparticle dynamics in nanostructures.