Efficient electron refrigeration using superconductor/spin-filter devices

TL;DR

This paper proposes and theoretically demonstrates a highly efficient electron refrigeration method using superconductor/spin-filter devices, significantly improving cooling power and temperature reduction in various junctions.

Contribution

It introduces a novel spin-filter-based cooling approach that outperforms conventional methods, enabling effective heat extraction in both ballistic and diffusive junctions.

Findings

Cooling power exceeds conventional coolers

Achieves electron temperature reduction from 300 mK to 50 mK

Applicable to detectors, sensors, and quantum devices

Abstract

Efficient electron-refrigeration based on a normal-metal/spin-filter/superconductor junction is proposed and demonstrated theoretically. The spin-filtering effect leads to values of the cooling power much higher than in conventional normal-metal/nonmagnetic-insulator/superconductor coolers and allows for an efficient extraction of heat from the normal metal. We demonstrate that highly efficient cooling can be realized in both ballistic and diffusive multi-channel junctions in which the reduction of the electron temperature from 300 mK to around 50 mK can be achieved. Our results indicate the practical usefulness of spin-filters for efficiently cooling detectors, sensors, and quantum devices.