Systematic study of d0-d KYZ (Y = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Z = al, Ga, In, Si, Ge, Sn, Pb, P, As, Sb, Bi, S, Se, Te) Heusler alloys

Abstract

The 126 half-Heusler alloys based on the KYZ (Y=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Z = Al, Ga, In, Si, Ge, Sn, Pb, P, As, Sb, Bi) in three different C1b structures (α, β and γ) have been investigated using Density Functional Theory. It was found that the α phase does not conserve cubic symmetry and its tetragonal ratio varies between 1.61 and 2.02. The α-type was shown to be energetically more favorable than the β and γ phases, which maintain cubic symmetry. Most of the studied phases were found to be mechanically unstable, but the 19 cubic phases were found to exhibit either semiconductor or half-metallic behavior with band gaps ranging between 0.48 and 3.18 eV. The calculated thermal lattice conductivity kL did not exceed 1.17 W/m·K, making these alloys promising as thermoelectric materials.