On-chip cooling by heating with superconducting tunnel junctions

¹ Dipartimento di Fisica dell'Università di Pisa - Largo Pontecorvo 3, I-56127 Pisa, Italy
² NEST Istituto Nanoscienze-CNR and Scuola Normale Superiore - I-56127 Pisa, Italy

Received: 17 September 2018
Accepted: 20 November 2018

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.