On-Chip Cooling by Heating with Superconducting Tunnel Junctions

TL;DR

This paper proposes an on-chip cooling device that uses heat input to generate a thermovoltage via a ferromagnetic insulator-superconductor junction, which then drives a series of tunnel junctions to achieve refrigeration at cryogenic temperatures.

Contribution

It introduces a novel solid-state cooling method leveraging heat-to-cooling conversion using N-FI-S and SINIS tunnel junctions, demonstrating effective on-chip refrigeration.

Findings

Efficient cooling of the normal metal island achieved.

Performance depends on input heat current and bath temperature.

System shows promise for scalable low-temperature energy management.

Abstract

Heat management and refrigeration are key concepts for nanoscale devices operating at cryogenic temperatures. The design of an on-chip mesoscopic refrigerator that works thanks to the input heat is presented, thus realizing a solid state implementation of the concept of cooling by heating. The system consists of a circuit featuring a thermoelectric element based on a ferromagnetic insulator-superconductor tunnel junction (N-FI-S) and a series of two normal metal-superconductor tunnel junctions (SINIS). The N-FI-S element converts the incoming heat in a thermovoltage, which is applied to the SINIS, thereby yielding cooling. The cooler's performance is investigated as a function of the input heat current for different bath temperatures. We show that this system can efficiently employ the performance of SINIS refrigeration, with a substantial cooling of the normal metal island. Its scalability and simplicity in the design makes it a promising building block for low-temperature on-chip energy management applications.