A non-invasive electron thermometer based on charge sensing of a quantum dot

TL;DR

This paper introduces a non-invasive quantum dot-based thermometer that accurately measures 2DEG temperature without passing current, compatible with other devices, and tunable independently of temperature.

Contribution

It presents a novel charge sensing thermometry method using a quantum dot and quantum point contact, achieving high accuracy and non-invasiveness.

Findings

Measured electronic temperatures between 97 mK and 307 mK.

Achieved temperature measurement accuracy up to 3 mK.

Method agrees with transport-based temperature measurements.

Abstract

We present a thermometry scheme to extract the temperature of a 2DEG by monitoring the charge occupation of a weakly tunnel-coupled 'thermometer' quantum dot using a quantum point contact detector. Electronic temperatures between 97 mK and 307 mK are measured by this method with an accuracy of up to 3 mK, and agree with those obtained by measuring transport through a quantum dot. The thermometer does not pass a current through the 2DEG, and can be incorporated as an add-on to measure the temperature simultaneously with another operating device. Further, the tuning is independent of temperature.