Two-dimensional epitaxial superconductor-semiconductor heterostructures: A platform for topological superconducting networks

A key challenge in fabrication of superconductor (S)-semiconductor (Sm) hybrid devices is forming highly transparent contacts between the active electrons in the semiconductor and the superconducting metal. In this work, we show that a near perfect interface and a highly transparent contact can be achieved using epitaxial growth of aluminum on an InAs two-dimensional electron system. We demonstrate that this material system, Al-InAs, satisfies all the requirements necessary to reach into the topological superconducting regime by individual characterization of the semiconductor two-dimensional electron system, superconductivity of Al, and performance of S-Sm-S junctions. This exciting development might lead to a number of useful applications ranging from spintronics to quantum computing.