Experimental realization of a Coulomb blockade refrigerator

TL;DR

This paper reports the experimental realization of a Coulomb blockade refrigerator using a single-electron transistor with superconducting inclusion, achieving cooling down to 15 mK and demonstrating potential for ultra-low temperature electronic cooling.

Contribution

It presents the first experimental implementation of a Coulomb blockade refrigerator with a superconducting inclusion, validating theoretical models at millikelvin temperatures.

Findings

Cooling down to 15 mK from base temperature

Agreement with theoretical models down to 80 mK

Potential for electronic cooling below 100 mK

Abstract

We present an experimental realization of a Coulomb blockade refrigerator (CBR) based on a single - electron transistor (SET). In the present structure, the SET island is interrupted by a superconducting inclusion to permit charge transport while preventing heat flow. At certain values of the bias and gate voltages, the current through the SET cools one of the junctions. The measurements follow theoretical model down to about 80 mK, which was the base temperature of the current measurements. The observed cooling increases rapidly with decreasing temperature in agreement with the theory, reaching about 15 mK drop at the base temperature. CBR appears as a promising electronic cooler at temperatures well below 100 mK.