Phase-controlled superconducting heat-flux quantum modulator

TL;DR

This paper proposes a phase-controlled superconducting heat-flux quantum modulator that uses phase-dependent heat currents in Josephson junctions to achieve temperature modulation at cryogenic temperatures, with potential applications in caloritronics.

Contribution

It introduces a novel device concept for a superconducting heat-flux modulator based on phase control in Josephson junctions, with detailed theoretical analysis and realistic performance estimates.

Findings

Temperature modulation amplitudes up to ~50 mK.

Flux-to-temperature transfer coefficients exceeding ~125 mK/Phi_0.

Operation frequency of a few MHz.

Abstract

We theoretically put forward the concept of a phase-controlled superconducting heat-flux quantum modulator. Its operation relies on phase-dependent heat current predicted to occur in temperature-biased Josephson tunnel junctions. The device behavior is investigated as a function of temperature bias across the junctions, bath temperature, and junctions asymmetry as well. In a realistic Al-based setup the structure could provide temperature modulation amplitudes up to ~50 mK with flux-to-temperature transfer coefficients exceeding ~125 mK/Phi_0 below 1 K, and temperature modulation frequency of the order of a few MHz. The proposed structure appears as a promising building-block for the implementation of novel-concept caloritronic devices operating at cryogenic temperatures.