Eduardo Lee

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Hybrid superconductor-semiconductor systems have been widely studied in the past decade for the development of novel quantum devices, with focus on both the topological and trivial regimes. Heat transport, on the other hand, remains relatively unexplored in such systems, and self-heating effects have been generally overlooked. This is unjustified considering that heating becomes increasingly more important at low temperatures (as heat dissipation mechanisms freeze out), with potential implications for device performance. In this work, we address the fundamental heating and cooling processes in devices based on full-shell InAs-Al nanowires [1,2]. To this end, we develop a technique dubbed “Joule spectroscopy” that detects Joule effect-driven superconductor-to-normal transitions in a device by tracking the suppression of the Andreev excess current. We further make use of the Little-Parks effect displayed by our nanowires to reveal the dominant heat dissipation mechanism for distinct superconducting regions of a hybrid device. We find that the main cooling mechanism for grounded and floating superconductors, namely quasiparticle diffusion and electron-phonon coupling, respectively, is different. As a result, we conclude that superconducting islands are approximately two orders of magnitude more susceptible to heating when compared to grounded superconductors.

[1] A. Ibabe et al., Nat. Commun. 14, 2873 (2023)

[2] A. Ibabe et al., Nano Lett. 24, 6488 (2024)

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IFIMAC
PH2
Contact: Daniel Rosenbach / Matteo Cacco