The 1/3-shot noise suppression in diffusive nanowires

TL;DR

This paper investigates how the shot noise suppression factor in diffusive nanowires depends on reservoir size and heat conductance, revealing that the universal 1/3 suppression is only approached with large reservoirs, explained by a heating model.

Contribution

It demonstrates the influence of reservoir size and heat conductance on shot noise suppression in diffusive nanowires, providing a heating model to explain the deviations from universality.

Findings

Suppression factor depends on reservoir size and heat conductance.

Small reservoirs lead to increased noise due to hot electron injection.

Universal 1/3 suppression is only achieved with large reservoirs.

Abstract

We report low-temperature shot noise measurements of short diffusive Au wires attached to electron reservoirs of varying sizes. The measured noise suppression factor compared to the classical noise value $2e\left| I\right| $ strongly depends on the electric heat conductance of the reservoirs. For small reservoirs injection of hot electrons increases the measured noise and hence the suppression factor. The universal 1/3-suppression factor can only asymptotically be reached for macroscopically large and thick electron reservoirs. A heating model based on the Wiedemann-Franz law is used to explain this effect.