Hybrid superconductor (SC)-semiconductor nanostructures have attracted great interest in the past years as a platform for exploring topological superconductivity and for the development of novel quantum devices. Despite advances in the growth of such nanostructures, fabricated devices still show a great deal of variability owing to disorder. Researchers at IFIMAC have developed a novel technique, based on the Joule effect, to provide a detailed characterization of the superconductivity in such hybrid devices, which can be used to uncover disorder-related fluctuations in device response.
Specifically, owing to the poor thermal conductivity of SCs at low temperatures, a significant increase in temperature is locally observed when a dissipative current flows through junctions of a hybrid SC-semiconductor device. When this temperature reaches the critical temperature of the SC, “dips” in conductance appear, signalling the transition of the superconducting contacts to the normal state. We demonstrate that these dips yield a fingerprint of the hybrid device, from which valuable information related to different sources of disorder (e.g., differences in the coherence length of the SC, the inverse superconducting proximity effect, etc.) can be extracted. [Full article]
