Shot noise in generic quantum dots: crossover from ballistic to diffusive transport

TL;DR

This paper investigates how shot noise in quantum dots transitions from ballistic to diffusive regimes, revealing how internal scattering affects noise suppression and transport characteristics.

Contribution

It introduces a comprehensive analysis of shot noise in quantum dots with variable impurity scattering, bridging the gap between ballistic and diffusive transport regimes.

Findings

Shot noise is suppressed below universal values in ballistic quantum dots.

Suppression varies with lead positions and regular/chaotic phase space regions.

Increasing impurity scattering restores universal shot noise levels.

Abstract

We study shot noise for generic quantum dots coupled to two leads and allow for an arbitrary strength of diffractive impurity scattering inside the dots. The ballistic quantum dots possess a mixed classical phase space, where regular and chaotic regions coexist. In absence of disorder, the noise is systematically suppressed below the universal value of fully chaotic systems, by an amount which varies with the positions of the leads. This suppression is due to the deterministic nature of transport through regular regions and along short chaotic trajectories, and disappears by increasing the scattering rate, which is incorporated by using the Poisson kernel of random matrix theory.