Abstract
Using rst-principles calculations within density functional theory, we explore the feasibility of
converting ternary half-Heusler compounds into a new class of three-dimensional topological insu-
lators (3DTI). We demonstrate that the electronic structure of unstrained LaPtBi as a prototype
system exhibits distinct band-inversion feature. The 3DTI phase is realized by applying a uni-
axial strain along the [001] direction, which opens a bandgap while preserving the inverted band
order. A de nitive proof of the strained LaPtBi as a 3DTI is provided by directly calculating the
topological Z2 invariants in systems without inversion symmetry. We discuss the implications of
the present study to other half-Heusler compounds as 3DTI, which, together with the magnetic
and superconducting properties of these materials, may provide a rich platform for novel quantum
phenomena.
