Electronic structure of topological insulators with MM′X half-Heusler compounds using density functional theory

The band structures and partial density of states of MM′X half-Heusler compounds as topological insulators have been simulated by using local density approximate + U. Results show that both the covalent M′–X bonds and the ionic M–M′ bands contribute the band structures, and the covalent bonds between M′ and X atoms decide the number of (E_Γ6 − E_Γ8) (Γ₆ and Γ₈ denote the twofold s-type orbitals and fourfold p-type orbitals and M, M′, and X show atoms located at different positions in the lattice); big size of |χ_M′ − χ_X| and small value of V are propitious to form topological insulators. - Highlights: • Both of covalent M′–X bonds and ionic M–M′ bands contribute band structures. • The covalent M′–X bonds decide the number of (E_Γ6 − E_Γ8). • Big value of |χ_M′ − χ_X| and small value of V are propitious to form topological insulators