Fermi-arc superconductivity in Dirac Semimetal Cd₃As₂

Cd₃As₂ is a three-dimensional Dirac semimetal with separated Dirac points in momentum space which are connected by Fermi arcs. In spite of their extensive studies via transport and spectroscopic approaches, the coupling of Fermi-arc states to superconductivity remains elusive. Here, we report the observation of proximity-induced Fermi-arc superconductivity in SC/Cd₃As₂ hybrid structures. The proximity gap in Fermi arcs is comparable to the parent superconductor which exhibits a flat conductance plateau in differential conductance spectra. The proximity-induced pairing gap on bulk states, however, is small and manifests itself as a zero-bias broad peak (ZBBP). Corroborated with theory, we further unveil a systematic suppression of the ZBBP and an appearance of conductance plateau when the Fermi-arc states become gradually dominant.