  Semiconductor-superconductor hybrids are widely used for realising complex
quantum phenomena such as topological superconductivity and spins coupled to
Cooper pairs. Accessing exotic regimes at high magnetic fields and increasing
operating temperatures beyond the state-of-the-art requires new, epitaxially
matched semiconductor-superconductor materials. The challenge is to generate
favourable conditions for heterostructure formation between materials with the
desired inherent properties. Here, we harness increased knowledge of
metal-on-semiconductor growth to develop InAs nanowires with epitaxially
matched, single crystal, atomically flat Pb films along the entire nanowire.
These highly ordered heterostructures have a critical temperature of 7 K and a
superconducting gap of 1.25 meV, which remains hard at 8.5 T, thereby more than
doubling the available parameter space. Additionally, InAs/Pb island devics
exhibit magnetic field-driven transitions from Cooper pair to single electron
charging; a pre-requisite for use in topological quantum computation.
Introducing semiconductor-Pb hybrids potentially enables access to entirely new
regimes for an array of quantum systems.
