Half-metallic ferrimagnetism in the full-Heusler compound Co2ScSb

The AlCu2Mn-type structure is found to be preferable energy wise than the CuHg2Ti-type structure for the full-Heusler Co2ScSb and exhibits half-metallic ferrimagnetism based on first-principles density-functional calculations. Calculations show that the total spin moment is 2 μB at the equilibrium lattice constant a0 = 6.21 Å, which agrees with the Slater–Pauling rule. The spin-up electrons are metallic, but the spin-down bands are semiconductor with a gap of 0.38 eV, and the spin-flip gap is of 0.24 eV. Half-metallicity is stable for a wide range of lattice constants.