Suppression of non-Poissonian shot noise by Coulomb correlations in ballistic conductors

TL;DR

This paper demonstrates that Coulomb correlations can significantly suppress non-Poissonian shot noise in ballistic conductors, with suppression levels depending on the energy distribution of injected carriers, opening new avenues for noise control.

Contribution

It reveals how Coulomb correlations suppress shot noise depending on the energy distribution of injected carriers, a novel insight into noise reduction in ballistic conductors.

Findings

Coulomb correlations can suppress shot noise significantly.

Suppression level depends on the shape of the energy distribution F_c(epsilon).

High-bias asymptotic behavior of shot-noise suppression is characterized.

Abstract

We investigate the current injection into a ballistic conductor under the space-charge limited regime, when the distribution function of injected carriers is an arbitrary function of energy F_c(epsilon). The analysis of the coupled kinetic and Poisson equations shows that the injected current fluctuations may be essentially suppressed by Coulomb correlations, and the suppression level is determined by the shape of F_c(epsilon). This is in contrast to the time-averaged quantities: the mean current and the spatial profiles are shown to be insensitive to F_c(epsilon) in the leading-order terms at high biases. The asymptotic high-bias behavior for the energy resolved shot-noise suppression has been found for an arbitrary (non-Poissonian) injection, which may suggest a new field of investigation on the optimization of the injected energy profile to achieve the desired noise-suppression level.