Superconductivity in a layered Li-Nb oxynitride

Abstract

A Li-Nb oxynitride was synthesized through ammonia nitridation of LiNb₃O₈. The structural analysis revealed that the crystal structure of this oxynitride consists of alternate stacking of octahedral and prismatic layers: Li and Nb ions coexist in the octahedral layer, while the prismatic site is preferentially occupied by Nb. This oxynitride shows a metallic behavior, accompanied by an abrupt drop of electrical resistivity at about 3 K. Furthermore, a large diamagnetism was observed below this temperature, suggesting the appearance of superconductivity.