Half-metallic ferromagnetism in C-doped ZnS: Density functional calculations

Using the full-potential linearized augmented plane wave method, we study the magnetism and electronic structures of C-doped ZnS (zinc-blende structure). Calculations indicate that C can induce stable ferromagnetic ground state in ZnS hosts. The magnetic moment of the 64-atom supercell (containing one C-S defect) is 2.00 mu(B). Low formation energy implies ZnS0.96 875C0.03 125 can be fabricated experimentally. Electronic structures show C-doped ZnS is p-type half-metallic ferromagnetic semiconductor and hole-mediated double exchange is responsible for the ferromagnetism. Relative shallow acceptor levels indicate C-doped ZnS is ionized easily at working temperatures. Several doped configurations calculations suggest ferromagnetic couplings exist between the doped carbon atoms.