Superconductivity in the antiperovskite Dirac-metal oxide Sr<sub>3-x</sub>SnO.

Oudah, Mohamed; Ikeda, Atsutoshi; Hausmann, Jan Niklas; Yonezawa, Shingo; Fukumoto, Toshiyuki; Kobayashi, Shingo; Sato, Masatoshi; Maeno, Yoshiteru · Nat Commun · 2016

basic_science · Level V

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Abstract

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<sub>3-x</sub>SnO with the transition temperature of around 5 K. Sr<sub>3</sub>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 <sup>3</sup>He-B in moderately hole-doped Sr<sub>3-x</sub>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.