Effect of electron-phonon scattering on shot noise in nanoscale junctions

TL;DR

This paper studies how electron-phonon inelastic scattering influences shot noise in nanoscale junctions, revealing bias-dependent behavior and potential for local temperature measurement.

Contribution

It introduces a model predicting how inelastic scattering affects shot noise and Fano factor in nanoscale junctions under different thermal conditions.

Findings

Inelastic scattering increases shot noise when local temperature exceeds vibrational mode energy.

Fano factor increases as the square root of bias voltage.

Inelastic contribution to Fano factor saturates at high thermal currents.

Abstract

We investigate the effect of electron-phonon inelastic scattering on shot noise in nanoscale junctions in the regime of quasi-ballistic transport. We predict that when the local temperature of the junction is larger than its lowest vibrational mode energy $eV_c$, the inelastic contribution to shot noise (conductance) increases (decreases) with bias as $V$ ($\sqrt{V}$). The corresponding Fano factor thus increases as $\sqrt{V}$. We also show that the inelastic contribution to the Fano factor saturates with increasing thermal current exchanged between the junction and the bulk electrodes to a value which, for $V>>V_c$, is independent of bias. A measurement of shot noise may thus provide information about the local temperature and heat dissipation in nanoscale conductors.