Effect of Oxygen Vacancy on Half Metallicity in Ni-doped CeO_2 Diluted Magnetic Semiconductor

摘要

The electronic and magnetic properties of Ni-doped CeO_2 diluted amgentic semiconductor (DMS) including the effect of oxygen vacancy (V_o) with doping concentration, x = 0.125 have been calculated using FPLAPW method based on Density Functional Theory (DFT) as implemented in WIEN2k. In the present supercell approach, the XC potential was constructed using GGA+U fo rmalism in which Coulomb correction is applied to standard GGA functional within the parameterization of Perdew-Burke-Ernzerhof (PBE). We have found that the ground state properties of bulk CeO_2 compound have been modified significantly due to the substitution of Ni-dopant at the cation (Ce) site with/without Vo and realized that the ferromagnetism in CeO_2 remarkably depends on the V_o concentrations. The presence of V_o, in Ni-doped CeO_2, can leads to strong ferromagnetic coupling between the nearest neighboring Ni-ions and induces a HMF in this compound. Such ferromagnetic exchange coupling is mainly attributed to spin splitting of Ni-d states, via electrons trapped in V_o. The HMF characteristics of Ni-doped CeO_2 including V_o makes it an ideal material for spintronic devices.