Electron Bunching in Stacks of Coupled Quantum Dots

TL;DR

This paper investigates how substrate phonons influence shot noise in coupled quantum dots, revealing that phonon interactions cause noise enhancement and asymmetry in current peaks at low temperatures.

Contribution

It provides new insights into the role of phonon-induced decoherence on shot noise in coupled quantum dot systems, especially under asymmetric coupling conditions.

Findings

Phonon interactions affect shot noise behavior.

Asymmetry in current peaks is due to spontaneous emission.

Shot noise can be sub- or super-Poissonian depending on conditions.

Abstract

We study the transport properties of two double quantum dots in a parallel arrangement at temperatures of a few Kelvin. Thereby, we show that decoherence entailed by the substrate phonons affects the shot noise. For asymmetric coupling between the dots and the respective lead, the current noise is sub-Poissonian for resonant tunneling, but super-Poissonian in the vicinity of the resonances. Our results indicate that phonon emission and absorption is responsible for the shot noise enhancement. The observed asymmetry of the peaks at low temperatures stems from spontaneous emission.