Determination of energy scales in few-electron double quantum dots

TL;DR

This paper presents methods to accurately determine energy scales in few-electron double quantum dots across different tunnel coupling regimes, addressing limitations of standard procedures in weak or asymmetric coupling scenarios.

Contribution

The authors develop new techniques for converting gate voltages to energy scales in quantum dots, applicable even in weak or asymmetric tunnel coupling regimes.

Findings

Strong variations in conversion factors across regimes

Methods extend to larger quantum dot arrays

Improved accuracy in energy scale determination

Abstract

The capacitive couplings between gate-defined quantum dots and their gates vary considerably as a function of applied gate voltages. The conversion between gate voltages and the relevant energy scales is usually performed in a regime of rather symmetric dot-lead tunnel couplings strong enough to allow direct transport measurements. Unfortunately this standard procedure fails for weak and possibly asymmetric tunnel couplings, often the case in realistic devices. We have developed methods to determine the gate voltage to energy conversion accurately in the different regimes of dot-lead tunnel couplings and demonstrate strong variations of the conversion factors. Our concepts can easily be extended to triple quantum dots or even larger arrays.