Counting statistics for electron capture in a dynamic quantum dot

TL;DR

This paper presents a high-precision, non-invasive method to analyze the probability distribution of electron counts in a quantum dot, distinguishing between thermal and athermal capture mechanisms to improve initialization strategies.

Contribution

It introduces a combined theoretical and experimental approach to identify the dominant electron capture mechanism in quantum dots, enhancing control over quantum dot initialization.

Findings

Identified the athermal capture mechanism in the quantum dot.

Validated the theoretical model with experimental data.

Provided strategies for improving quantum dot initialization.

Abstract

We report non-invasive single-charge detection of the full probability distribution $P_n$ of the initialization of a quantum dot with $n$ electrons for rapid decoupling from an electron reservoir. We analyze the data in the context of a model for sequential tunneling pinch-off, which has generic solutions corresponding to two opposing mechanisms. One limit considers sequential "freeze out" of an adiabatically evolving grand canonical distribution, the other one is an athermal limit equivalent to the solution of a generalized decay cascade model. We identify the athermal capturing mechanism in our sample, testifying to the high precision of our combined theoretical and experimental methods. The distinction between the capturing mechanisms allows to derive efficient experimental strategies for improving the initialization.