Shot noise in diffusive conductors: A quantitative analysis of electron-phonon interaction effects

TL;DR

This paper provides a quantitative analysis of how electron-phonon interactions influence shot noise in diffusive conductors, revealing that significant noise suppression occurs only at high ratios of sample length to energy relaxation length.

Contribution

The study introduces a detailed quantitative model using the drift-diffusion-Langevin equation to analyze shot noise considering electron-phonon interactions in diffusive conductors.

Findings

Shot noise drops to half its mesoscopic value only at high energy relaxation ratios.

Significant shot noise persists in macroscopic conductors at low temperatures.

The analysis highlights the importance of electron-phonon interactions in noise behavior.

Abstract

Using the 'drift-diffusion-Langevin' equation, we have quantitatively analyzed the effects of electron energy relaxation via their interaction with phonons, generally in presence of electron-electron interaction, on shot noise in diffusive conductors. We have found that the noise power $ S_I(\omega )$ (both at low and high observation frequencies $\omega $) drops to half of its 'mesoscopic' value only at $\beta \gtrsim 100,$ where $\beta $ is the ratio of the sample length $L$ to the energy relaxation length $l_{% {\rm ph}}$ (the latter may be much larger then the dephasing length). It means in particular that at low temperatures the shot noise may be substantial even when $L\sim 10^{-2}$ -- $10^{-1}$ cm, and the conductor is 'macroscopic' in any other respect.