Ferromagnetism in RaBi with Zinc-Blende and Wurtzite Structures: Ab-initio Prediction
Using density-functional theory within the generalized-gradient approximation, we explore the magnetic behavior induced by nonmagnetic atoms Ra and Bi in RaBi binary compound in five crystalline structures (rocksalt (B1), CsCl (B2), ZB (B3), WZ (B4) and NiAs (B8[Formula: see text]. In all the structures considered, the ferromagnetic (FM) phase is energetically less favorable compared to the paramagnetic phase except in the ZB and WZ structures. In the (FM) ZB and WZ structures, we obtained that the spin polarized 6[Formula: see text] orbitals of bismuth in the RaBi compound results in a half-metallic (HM-FM) ferromagnet with an integer magnetic moment of 1[Formula: see text][Formula: see text] per formula unit. We calculated spin flip gaps (half-metallic gaps) of 0.16 and 0.18[Formula: see text]eV within GGA-PBE approach, 0.40[Formula: see text]eV and 0.33[Formula: see text]eV with mBJ-GGA-PBE approach for ZB and WZ structures, respectively. The RaBi compound in ZB and WZ structures would have potential application in spintronic devices.