Hybrid Superconducting Devices Based on Quantum Wires

This article reviews the experimental progress in hybrid superconducting devices based on quantum wires, in the form of semiconductor nanowires or carbon nanotubes, which are coupled to superconducting electrodes. It also presents a series of recent examples which illustrate the key phenomena that have allowed detailed investigations of important scenarios, including individual impurities on superconductors and proximitized systems that may hold Majorana quasiparticles. After describing experimental aspects of hybrid devices, including materials and fabrication techniques, the article considers superconducting junctions with normal quantum dots (QDs). It then turns to experiments on superconductivity-enhanced QD spectroscopy, sub-gap states in hybrid QDs, and non-local signals in Cooper pair splitter devices. Finally, it discusses the growth of epitaxial semiconductor–superconductor nanowire hybrids.