Shot Noise in Mesoscopic Transport Through Localised States

TL;DR

This paper demonstrates how shot noise measurements reveal details of electron transport mechanisms like hopping and resonant tunnelling in localized states, showing suppression or enhancement depending on the process and interactions involved.

Contribution

It provides new insights into shot noise behavior in mesoscopic transport, highlighting the effects of Coulomb interactions and barrier distributions on noise characteristics.

Findings

Shot noise is suppressed in hopping via multiple states.

Resonant tunnelling through a single impurity shows noise enhancement.

Coulomb interactions significantly increase shot noise in resonant channels.

Abstract

We show that shot noise can be used for studies of hopping and resonant tunnelling between localised electron states. In hopping via several states, shot noise is seen to be suppressed compared with its classical Poisson value $S_I=2eI$ ($I$ is the average current) and the suppression depends on the distribution of the barriers between the localised states. In resonant tunnelling through a single impurity an enhancement of shot noise is observed. It has been established, both theoretically and experimentally, that a considerable increase of noise occurs due to Coulomb interaction between two resonant tunnelling channels.