Phase Stability and Electronic Structure of Heusler Alloys Ti2VZ (Z = Al, As, Ga, Ge, In, P, Sb, Si, Sn)

The article deals with the chemical stability, structural, magnetic, and electronic properties of Ti2VZ (Z = Al, As, Ga, Ge, In, P, Sb, Si, Sn) alloys using density functional theory methods. All compounds are found thermodynamically stable, and their stability correlates with the valence electron concentration (e/a) and decreases for heavier elements. The magnetic properties depend on composition and the degree of tetragonality: in the cubic phase, an increase in e/a reduces magnetization intensity, whereas lattice distortion increases it. Half-metallic behavior with 100 % spin polarization appears at e/a = 4 and 4,25, while Ti2VSb (e/a = 4,5) acquires a semiconducting state with a narrow gap ~0,1 eV. The results agree with PBE functional calculations and demonstrate the advantages of the SCAN functional for accurate description of complex alloys.