  The discovery of materials that simultaneously host different phases of
matter has often initially confounded, but ultimately enhanced, our basic
understanding of the coexisting types of order. The associated intellectual
challenges, together with the promise of greater versatility for potential
applications, have made such systems a focus of modern materials science. In
particular, great efforts have recently been devoted to making semiconductors
ferromagnetic and metallic ferromagnets superconducting. Here we report the
unprecedented observation of a heavily donor-doped ferromagnetic semiconductor,
SmN, becoming superconducting with ferromagnetism remaining intact. The
extremely large exchange splitting of the conduction and valence bands in this
material necessitates that the superconducting order hosted by SmN is of an
unconventional triplet type, most likely exhibiting p-wave symmetry. Short
range spin fluctuations, which are thought to be the cause of pairing
interactions in currently known triplet superconductors, are quenched in SmN,
suggesting its superconductivity to be the result of phonon- or
Coulomb-mediated pairing mechanisms. This scenario is further supported by the
inferred heavy mass of superconducting charge carriers. The unique near-zero
magnetisation associated with the ferromagnetic state in SmN further aids its
coexistence with superconductivity. Presenting this novel material system where
semiconducting, ferromagnetic and superconducting properties are combined
provides a versatile new laboratory for studying quantum phases of matter.
Moreover it is a major step towards identifying materials that merge
superconductivity and spintronics, urgently needed to enable the design of
electronic devices with superior functionality.
