Superconductivity in the antiperovskite Dirac-metal oxide Sr3−xSnO

Investigations of perovskite oxides triggered by the discovery of high-temperature and unconventional superconductors have had crucial roles in stimulating and guiding the development of modern condensed-matter physics. Antiperovskite oxides are charge-inverted counterpart materials to perovskite oxides, with unusual negative ionic states of a constituent metal. No superconductivity was reported among the antiperovskite oxides so far. Here we present the first superconducting antiperovskite oxide Sr 3− x SnO with the transition temperature of around 5 K. Sr 3 SnO possesses Dirac points in its electronic structure, and we propose from theoretical analysis a possibility of a topological odd-parity superconductivity analogous to the superfluid 3 He-B in moderately hole-doped Sr 3− x SnO. We envision that this discovery of a new class of oxide superconductors will lead to a rapid progress in physics and chemistry of antiperovskite oxides consisting of unusual metallic anions. Superconductivity has not been observed in any antiperovskite oxide up to now. Here Oudah et al . report superconducting transition around 5 K in antiperovskite oxide Sr 3− x SnO, making it a new class of oxide superconductors.