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Thermal superconducting quantum interference proximity transistor


Superconductors are excellent thermal insulators at low temperatures owing to the presence of an energy gap in their density of states1. Through the so-called proximity effect2, superconductors can influence the density of states of nearby metallic or superconducting wires. In this way, the local density of states of a wire can be tuned by controlling the phase bias (φ) imposed across it3. Here we demonstrate a thermal superconducting quantum interference proximity transistor (T-SQUIPT) that enables the phase control of heat currents by exploiting the superconducting proximity effect. Our T-SQUIPT device comprises a quasi-one-dimensional aluminium nanowire forming the weak link embedded in a superconducting ring4,5. Controlling the phase bias by changing the magnetic flux through the ring shows temperature modulations of up to 16 mK, yielding a temperature-to-flux transfer function that reaches approximately 60 mK Φ0–1. We also demonstrate a hysteretic dependence of the local density of states of T-SQUIPTs on the applied magnetic field due to phase-slip transitions. This allows the T-SQUIPT device to operate as a phase-tunable thermal memory6,7, where the information is encoded in the temperature of the metallic mesoscopic island.

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Fig. 1: Operation principle and implementation of T-SQUIPT.
Fig. 2: Low-temperature behaviour of T-SQUIPT.
Fig. 3: Bath-temperature evolution of the T-SQUIPT behaviour.
Fig. 4: T-SQUIPT operated as a thermal memory cell.

Data availability

All other data that support the plots within this paper and other findings of this study are available from the corresponding author F.G. upon reasonable request.

Code availability

The codes that support the findings of this study are available from the corresponding author E.S. upon reasonable request.


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We acknowledge the European Research Council under grant agreement no. 899315-TERASEC, and the EU’s Horizon 2020 research and innovation programme under grant agreement no. 800923 (SUPERTED) and no. 964398 (SUPERGATE) for partial financial support.

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Authors and Affiliations



E.S. and F.G. conceived the experiment. N.L. fabricated the samples with inputs from F.P. N.L., F.P. and E.S. performed the measurements. N.L. analysed the experimental data with inputs from F.P., E.S. and F.G. E.S. and F.G. developed the theoretical model. N.L and F.P. wrote the manuscript with inputs from all the authors. All the authors equally discussed the results and their implications at all the stages.

Corresponding authors

Correspondence to Elia Strambini or Francesco Giazotto.

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The authors declare no competing interests.

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Nature Physics thanks Olivier Maillet and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–6 and refs. 1–7.

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Ligato, N., Paolucci, F., Strambini, E. et al. Thermal superconducting quantum interference proximity transistor. Nat. Phys. 18, 627–632 (2022).

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