The T-SQUIPT: Thermal Superconducting Quantum Interference Proximity Transistor

Superconducting materials are known to be good thermal insulators at sufficiently low temperatures thanks to the presence of the energy gap in their density of states (DOS). Yet, the proximity effect allows to tune the local DOS of a metallic wire by controlling the phase biasing imposed across it. As a result, the wire thermal resistance can be largely tuned by phase manipulation. In this talk I will show the experimental implementation of efficient control of thermal current by phase tuning the superconducting proximity effect. This is achieved by using the magnetic flux-driven modulation of the DOS of a quasi one-dimensional aluminum nanowire forming a weak-link embedded in a superconducting loop [1]. Moreover, phase-slip events occurring in the nanowire are able to induce a hysteretic dependence of its local DOS on the direction of the applied magnetic field. Thus, we also demonstrate the operation of the nanovalve as a phase-tunable thermal memory [1, 2], thereby encoding information in the local temperature of a metallic electrode nearby connected. Besides quantum physics, our results are relevant for the design of innovative phase-coherent caloritronics devices such as thermal valves and temperature amplifiers, which are promising nanostructures for the realization of heat logic architectures.

References:

[1] N. Ligato, F. Paolucci, E. Strambini and F. Giazotto, Nat. Phys.(2022). https://doi.org/10.1038/s41567-022-01578-z.

[2] N. Ligato, E. Strambini, F. Paolucci and F. Giazotto, Nat. Commun. 12, 5200 (2021).

The seminar is realized in the framework of the funded projects:

- SPECTRUM (GA 101057977), EC-European Innovation Council
- SUPERGATE (GA 964398), UE H2020-FETOPEN-2018-2020
- SUPERTED (GA 800923), UE H2020-FETOPEN-2016-2017