Shot noise spectroscopy on a semiconductor quantum dot in the elastic and inelastic cotunneling regimes

TL;DR

This study uses shot noise spectroscopy to distinguish elastic and inelastic cotunneling in a semiconductor quantum dot, revealing different Fano factors that shed light on the microscopic transport mechanisms.

Contribution

It provides the first detailed shot noise analysis distinguishing elastic and inelastic cotunneling regimes in a semiconductor quantum dot.

Findings

Poissonian shot noise in elastic cotunneling with Fano factor ~1

Super-Poissonian shot noise in inelastic cotunneling with Fano factor between 1 and 3

Differences in Fano factors reveal microscopic transport mechanisms

Abstract

We report shot noise spectroscopy on a semiconductor quantum dot in a cotunneling regime. The DC conductance measurements show clear signatures of both elastic and inelastic cotunneling transport inside a Coulomb diamond. We observed Poissonian shot noise with the Fano factor $F\approx 1$ in the elastic cotunneling regime, and super-Poissonian Fano factor $1<F<3$ in the inelastic cotunneling regime. The differences in the value of the Fano factor between elastic and inelastic processes reveal the microscopic mechanisms involved in the cotunneling transport.