Electronic cooling above 1.5 K

Low temperatures are important enablers in many applications of technological relevance, from superconducting quantum computing to sensitive radiation detection. Cryogenic temperatures below few kelvin are traditionally achieved by pumped helium systems. Alternatively, tunnel junction based on-chip cooling methods have been studied for several decades, yielding proof-of-concept demonstrators at various temperatures below 1 K. We extend the range by first demonstration of absolute electronic cooling from bath temperatures near 2 K by using superconducting tunnel junction devices for cooling and thermometry.