Eduardo Lee

Abstract:

Hybrid superconductor-semiconductor devices have been intensively studied in the past decade owing to prospects of applications in quantum technologies. Crucially, towards this goal, an impressive improvement in the quality of materials has been achieved in recent years. Nonetheless, fabricated devices arguably still show a great deal of variability, each being effectively unique. Here, we demonstrate that Joule heating can be used as a powerful tool for the characterization of such devices. Concretely, we show that the transition of the superconducting leads to the normal state by the Joule effect can be used as a spectroscopical signature in transport of the superconductivity of each lead separately and in a single measurement, thus readily providing a “fingerprint” of each device. We demonstrate the potential of the technique by obtaining detailed information of devices based on hybrid epitaxial Al-InAs nanowires. In particular, we study full shell wires, also in the Little-Parks, and uncover differences in the superconducting coherence lengths of the leads, inhomogeneous covering from the epitaxial shell, and the inverse superconducting proximity effect. Our work also underscores the importance of heating effects in hybrid devices, a topic which has been so far largely overlooked.