Three-dimensional topological insulators: case of quaternary Heusler compounds

The feasibility of converting quaternary Heusler compounds XX’MZ (X=Sc, La; X’=Sc, Y; M=Ru, Fe; Z=Pb) into three-dimensional topological insulators was investigated by first-principle calculations. It is found that the topological insulating state can be achieved in these quaternary Heusler compounds by the proper strain engineering or the substitution of elements. Most of these compounds investigated in this paper have a negative formation energy, which implies that they are possible to be synthesized in reality.