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arXiv · 2507.11327

Coulomb blockade thermometry based nanocalorimetry

Mari C. Cole·Maximilian T. Pelly·Craig V. Topping·Thomas Reindl·Ulrike Waizmann·Jürgan Weis·Andreas W. Rost
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Abstract

Specific heat is a powerful probe offering insights into the entropy and excitation spectrum of the studied material. While it is well established, a key challenge remains the measurements of microcrystals or thin films especially in the sub-Kelvin, high magnetic field regime. Here we present a setup combining the high sensitivity of SiN$_x$ membrane based calorimetry with the absolute accuracy of Coulomb blockade thermometry to realise a nanocalorimeter for such tasks. The magnetic field independent technique of Coulomb blockade thermometry provides an on-platform thermometer combining a primary thermometry mode for in-situ calibration with a fast secondary mode suitable for specific heat measurements. The setup is validated using measurements of a 20 $\mu$g sample of Sr$_3$Ru$_2$O$_7$ achieving a resolution on the order of 0.1 nJ/K at 500 mK and an absolute accuracy limited by the determination of the sample's mass. Measurements of CeRh$_2$As$_2$ further highlight the benefits of measuring microcrystals with such a device.

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Mari C. Cole, Maximilian T. Pelly, Craig V. Topping, Thomas Reindl, Ulrike Waizmann, Jürgan Weis, Andreas W. Rost. 2025-07-15. Coulomb blockade thermometry based nanocalorimetry. https://doi.org/10.1063/5.0257902

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