Efficient electronic cooling above 2 K by niobium-based superconducting tunnel junctions
Abstract
Replacing the bulky cryoliquid-based cooling stages of cryoenabled instruments by chip-scale refrigeration is envisioned to disruptively reduce the system size similar to microprocessors did for computers. Electronic refrigerators based on superconducting tunnel junctions have been anticipated to provide a solution, but reaching the necessary above the 1-K operation temperature range has remained a goal out of reach for several decades. We show efficient electronic refrigeration by Al-AlO-Nb superconducting tunnel junctions starting from bath temperatures above 2 K. The junctions can deliver electronic cooling power up to approximately mW/mm, which enables us to demonstrate tunnel-current-driven electron temperature reduction from 2.4 K to below 1.6 K (34% relative cooling) against the phonon bath. Our work shows that the key material of integrated superconducting circuits - niobium - enables powerful cryogenic refrigerator technology. This result is a prerequisite for practical cryogenic chip-scale refrigerators and, at the same time, it introduces a new electrothermal tool for quantum heat-transport experiments.
Cite
@article{arxiv.2403.08655,
title = {Efficient electronic cooling above 2 K by niobium-based superconducting tunnel junctions},
author = {J. Hätinen and A. Ronzani and R. P. Loreto and E. Mykkänen and A. Kemppinen and K. Viisanen and T. Rantanen and J. Geisor and J. Lehtinen and M. Ribeiro and J-P. Kaikkonen and O. Prakash and V. Vesterinen and W. Förbom and E. T. Mannila and M. Kervinen and J. Govenius and M. Prunnila},
journal= {arXiv preprint arXiv:2403.08655},
year = {2024}
}