Selected Publications

Optimized Proximity Thermometer for Ultrasensitive Detection

Bayan Karimi, Danilo NikoliÄ?, Tuomas Tuukkanen, Joonas T. Peltonen, Wolfgang Belzig, Jukka P. Pekola

We present a set of experiments to optimize the performance of a noninvasive thermometer based on proximity superconductivity. Current through a standard tunnel junction between an aluminum superconductor and a copper electrode is controlled by the strength of the proximity induced to this normal metal, which in turn is determined by the position of a direct superconducting contact from the tunnel junction. Several devices with different distances are tested. We develop a theoretical model based on Usadel equations and dynamic Coulomb blockade that reproduces the measured results and yields a tool to calibrate the thermometer and to optimize it further in future experiments. We also propose an analytic formula that reproduces the experimental data for a wide range of temperatures.

Phys. Rev. Applied 13, 054001 (2020)

doi: 10.1103/PhysRevApplied.13.054001