Superconductivity in an Inorganic Electride 12CaO·7Al₂O₃:e^-

Abstract

An inorganic electride, 12CaO·7Al 2 O 3:e -, synthesized by exclusively replacing oxygen ions in the sub-nanometer-sized cages of 12CaO·7Al 2 O 3 crystal with electrons exhibits a superconducting transition at a temperature ( T c ) of ∼0.4 K. T c varies in the range of 0.14−0.4 K with the concentration of anionic electrons, which are primarily distributed over crystallographic spaces without occupying any particular framework ions. The precursor of electride is composed of representative metal oxides, which are electrical insulators. Thus, the exotic crystal structure of electrides provides an insight for a material platform to realize a new superconductor.