Prediction of Half-Metallic Ferromagnetism in Cu- and K-Doped MgS: A Comparative Study

Ab initio calculations based on density functional theory have been used to comparatively investigate the electronic and magnetic properties of two non-magnetic ions (Cu, K)-doped magnesium sulfide. The results obtained indicate that the ferromagnetic phase is always energetically favorable than the paramagnetic one. It is also found that these ternary alloys are half-metallic ferromagnets with a total magnetic moment of 1.00 μ B per supercell. The ferromagnetism is induced by hybridization between Cu 3d and its nearest neighboring S 3p in Cu-doped MgS, while it originates in the spin polarization of the p shell of anions S in K-doped MgS. Our results make these compounds attractive materials for possible spintronics devices.