Comparison of Coulomb Blockade Thermometers with the International Temperature Scale PLTS-2000

TL;DR

This paper compares Coulomb blockade thermometers with the international temperature scale PLTS-2000, demonstrating about 1% agreement above 0.25 K and analyzing thermalization issues at lower temperatures.

Contribution

It provides a high-accuracy comparison between Coulomb blockade thermometers and the PLTS-2000 scale across a broad temperature range.

Findings

Approximately 1% agreement above 0.25 K

Thermalization issues at lower temperatures

Numerical modeling of electron-phonon decoupling

Abstract

The operation of the primary Coulomb blockade thermometer (CBT) is based on a measurement of bias voltage dependent conductance of arrays of tunnel junctions between normal metal electrodes. Here we report on a comparison of a CBT with a high accuracy realization of the PLTS-2000 temperature scale in the range from 0.008 K to 0.65 K. An overall agreement of about 1% was found for temperatures above 0.25 K. For lower temperatures increasing differences are caused by thermalization problems which are accounted for by numerical calculations based on electron-phonon decoupling.