Counting statistics of hole transfer in a p-type GaAs quantum dot with dense excitation spectrum

TL;DR

This study investigates hole transfer in a p-type GaAs quantum dot, revealing how dense excited states influence tunneling rates and charge transfer statistics, with implications for understanding heavy hole systems.

Contribution

It provides the first detailed analysis of counting statistics and tunneling rates in a p-type GaAs quantum dot with dense excited states, including factorial cumulants.

Findings

Tunneling rates increase super-linearly with bias.

Dense excited states significantly affect transport properties.

Both normal and factorial cumulants are relevant for interacting systems.

Abstract

Low-temperature transport experiments on a p-type GaAs quantum dot capacitively coupled to a quantum point contact are presented. The time-averaged as well as time-resolved detection of charging events of the dot are demonstrated and they are used to extract the tunnelling rates into and out of the quantum dot. The extracted rates exhibit a super-linear enhancement with the bias applied across the dot which is interpreted in terms of a dense spectrum of excited states contributing to the transport, characteristic for heavy hole systems. The full counting statistics of charge transfer events and the effect of back action is studied. The normal cumulants as well as the recently proposed factorial cumulants are calculated and discussed in view of their importance for interacting systems.