Search for New Half-Metallic Ferromagnets in Quaternary Diamond-Like Compounds I–II{sub 2}–III–VI{sub 4} and I{sub 2}–II–IV–VI{sub 4} (I = Cu; II = Mn, Fe, Co; III = In; IV = Ge, Sn; VI = S, Se, Te)
The structural, electronic, and magnetic properties I–II{sub 2}–III–VI{sub 4} and I{sub 2}–II–IV–VI{sub 4} are investigated firstly by using the first-principles calculations. The investigation was done using the ab initio full-potential linearized augmented plane wave (FPLAPW) method where the exchange–correlation potential was calculated with the frame of GGA and GGA+U. The theoretically predicted lattice parameters for I–II{sub 2}–III–VI{sub 4} and I{sub 2}–II–IV–VI{sub 4} alloys are in good agreement with existing experimental measurements. The possibility of half-metallic ferromagnetism in I–II{sub 2}–III–VI{sub 4} and I{sub 2}–II–IV–VI{sub 4} (I = Cu; II = Mn, Fe, Co; III = In; IV = Ge, Sn; VI = S, Se, Te) was analyzed by electronic band structure and density of states calculations. We found that Cu{sub 2}CoGeS{sub 4}, Cu{sub 2}FeGeS{sub 4}, Cu{sub 2}FeSnS{sub 4}, and CuMn{sub 2}InSe{sub 4} compounds exhibit a complete half-metallic characteristic with a total spin moment of 3.00, 4.00, 4.00, and 10.00 μ{sub B} and direct band gap of (Eg ↑ = 0.63 eV), (Eg ↑ = 0.90 eV), (Eg ↑ = 0.31 eV), and (Eg ↓ = 1.10 eV), respectively. These results may be of interest for spintronic applications.