First-principles investigation of half-metallic ferromagnetism of half-Heusler compounds XYZ

• The structural stability and half-metallicity of half-Heusler compounds XYZ are investigated using ab initio calculations.
• Nine compounds are predicted to be half-metals with the gap of 0.07–0.67 eV.
• It is expected that these half-metals would be realized in the form of thin films under metastable conditions.
• Their half-metallicities are robust against lattice distortion.

We investigate the electronic structure and magnetism of half-Heusler compounds XYZ (X, Y=V, Cr, Mn, Fe, Co and Ni; Z=Al, Ga, In, Si, Ge, Sn, P, As, and Sb) using the ab initio density functional theory calculations. Nine half-metals with half-Heusler structure have been predicted with the half-metallic gap of 0.07–0.67 eV. The calculations show that the formation energies for these nine half-Heusler compounds range from −1.32 to −0.12 eV/f.u., and for CoCrSi, CoCrGe, CoFeGe, CoMnSi, CoMnGe, FeMnGe and FeMnAs, the total energy differences between the half-Heusler structure and the corresponding ground-state structure are small (0.07–0.76 eV/f.u.), thus it is expected that they would be realized in the form of thin films under metastable conditions for spintronic applications. The stability of the half-metallicity of CoCrGe and FeMnAs to the lattice distortion is also investigated in detail.