Sub-50-mK Electronic Cooling with Large-Area Superconducting Tunnel Junctions

Abstract

Experiments conducted below 0.1 K require expensive, complicated cryogenic apparatus. What if an integrated solid-state device could be used instead? The authors present just such an on-chip refrigerator, based on a superconductor/normal-metal junction, that chills down to 30 mK with remarkable cooling power. This provides a means to reduce thermal noise in e.g. qubits, SQUIPT magnetometers, or the sensitive detectors required for astronomy experiments.