Synthesis and property of layer structured nitride superconductors by deintercalation

Abstract

A new electron-doping method for β-MNCl (M = Zr, Hf) has been developed by the reactions with metal azides AN₃ (A = Na, K, Rb). On heating, the azides were decomposed into the respective alkali metals and nitrogen. The chlorine atoms between the layers were partially deintercalated by the alkali metals, resulting in the electron-doping into the nitride layers. The compounds showed superconductivity of Tc about 14.0 K and 24.0 K for β-ZrNCl and β-HfNCl, respectively.