Abstract
Temperatures below 1 mK on-chip hold great potential for quantum physics but present a great challenge due to the lack of suitable thermometry and the detrimental pulse-tube vibrations of cryogen-free refrigerators. Here, we solve the pulse-tube problem using a rigidly wired metallic sample holder, which provides a microkelvin environment with low heat leaks despite the vibrations. Further, we demonstrate an improved type of temperature sensor, the gate Coulomb blockade thermometer (gCBT), employing a gate metallization covering the entire device. This immunizes against nanofabrication imperfections and uncontrollable offset charges, and extends the range to lower temperatures compared to a junction CBT with the same island capacitance, here down to 160 K for a 10% accuracy. Using on- and off-chip cooling, we demonstrate electronic temperatures as low as 224 7 K, remaining below 300 K for 27 hours, thus providing time for experiments. Finally, we give an outlook for cooling below 50 K for a future generation of microkelvin transport experiments.
4 More- Received 28 October 2021
- Accepted 24 July 2022
- Corrected 13 October 2022
DOI:https://doi.org/10.1103/PhysRevResearch.4.033225
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Corrections
13 October 2022
Correction: The byline footnote indicating the equal contribution of the first and second authors was missing and has been inserted.