New class of high-Tc diluted ferromagnetic semiconductors based on CaO without transition metal elements

We propose new-type ferromagnetic semiconductors based on CaO and K2S without any transition metal elements. These materials show transparent and half-metallic ferromagnetism if the deep-impurity-band width (W) induced by doping of C, N, Si, or Ge impurities, and the electron-correlation energy (U) satisfy the Stoner's condition of highly correlated electron system (U > W). Based on our first-principles calculations, we demonstrate that these materials satisfy the Stoner's condition, and could be new candidates for transparent and half-metallic DMSs.