Cooling electrons from 1 K to 400 mK with V-based nanorefrigerators

TL;DR

This paper demonstrates a V-based superconducting nanorefrigerator that effectively cools electrons from 1 K to 400 mK, showcasing potential for on-chip cooling applications from above 1 K to millikelvin temperatures.

Contribution

It introduces a novel V-based superconducting nanorefrigerator architecture capable of significant electron cooling from 1 K to 400 mK, extending refrigeration techniques to higher temperatures.

Findings

Achieved electronic cooling down to 400 mK from 1 K.

Demonstrated a cooling power of ~20 pW at 1 K.

Proposed architecture enables multi-stage cooling from above 1 K to mK regime.

Abstract

The fabrication and operation of V-based superconducting nanorefrigerators is reported. Specifically, electrons in an Al island are cooled thanks to hot-quasiparticle extraction provided by tunnel-coupled V electrodes. Electronic temperature reduction down to 400 mK starting from 1 K is demonstrated with a cooling power ~20 pW at 1 K for a junction area of 0.3 micron^2. The present architecture extends to higher temperatures refrigeration based on tunneling between superconductors and paves the way to the implementation of a multi-stage on-chip cooling scheme operating from above 1 K down to the mK regime.