Study of New d0 Half-Metallic Half-Heusler Alloy MgCaB: First-Principles Calculations

Using first-principles calculations based on the density functional theory (DFT) within the generalized gradient approximation(GGA) for the exchange correlation potential, we have studied the structural, elastic, electronic, and magnetic properties of new d(0) half Heusler alloy MgCaB. We found that MgCaB is energetically, mechanically, and chemically stable in the alpha phase exhibiting ductile nature with negative cohesive and formation energies confirming the possibility of its synthesis experimentally. Our calculations predicate the half-metallicity of this alloy with total magnetic moment of 1.000 mu(B) per formula unit, well consistent with Slater-Pauling rule (M-tot = (8 -Z(tot))mu(B)). The obtained results show that MgCaB has a majority band gap of 0.834 eV with a half-metallic gap of 0.305 eV. The origin of this gap is well discussed. It was also found that half-Heusler alloy MgCaB is a robust half-metallic with respect to the lattice contraction or dilatation. It preserved its half-metallicity in a wide range of lattice constants of 5.47-7.32 angstrom, and it is considered as nearly gapless half-metallic ferromagnet for lattice parameters range of 7.32-8.14 angstrom which makes it a worthwhile candidate for applications in spintronic field.