Highly efficient phase-tunable photonic thermal diode

TL;DR

This paper demonstrates a highly efficient, phase-tunable photonic thermal diode using a superconducting-normal metal system, enabling controlled heat transfer with potential applications in quantum circuit cooling.

Contribution

It introduces a novel phase-controlled thermal diode with extremely high rectification, tunable via magnetic flux in a SQUID, advancing thermal management in superconducting devices.

Findings

Rectification factor up to 10^8 in aluminum superconducting island

Photon-mediated heat transport surpasses electron-phonon contribution at low temperatures

Thermal diode behavior can be tuned by magnetic flux in a SQUID

Abstract

We investigate the photon-mediated thermal transport between a superconducting electrode and a normal metal. When the quasiparticle contribution can be neglected, the photon-mediated channel becomes an efficient heat transport relaxation process for the superconductor at low temperatures, being larger than the intrinsic contribution due to the electron-phonon interaction. Furthermore, the superconductor-normal metal system acts as a nearly-perfect thermal diode, with a rectification factor up to $10^8$ for a realistic aluminum superconducting island. The rectification factor can be also tuned in a phase-controlled fashion through a non-galvanic coupling, realized by changing the magnetic flux piercing a superconducting quantum interference device (SQUID), which modifies the coupling impedance between the superconductor and the normal metal. The scheme can be exploited for passive cooling in superconducting quantum circuits by transferring heat toward normal metallic pads where it dissipates more efficiently or for more general thermal management purposes.