Figure 1: PtLuSb bulk crystallographic and electronic structure.
From: Observation of a topologically non-trivial surface state in half-Heusler PtLuSb (001) thin films
(a) Half-Heusler C1b crystal structure consisting of three interpenetrating face-centred-cubic sub-lattices. For PtLuSb, the platinum, lutetium and antimony atoms are denoted by the green, blue and orange spheres, respectively. (b) Half-Heusler bulk Brillouin zone with the (001) surface Brillouin zone projection. The high-symmetry surface Brillouin zone points are defined as 
(0, 0), 
(k0/2, 0), 
(0, k0/2) and 
(k0/2, k0/2), where, for PtLuSb (001), the surface unit momentum k0=2π(√2/a0)=1.376 Å−1. (c) First-principles calculated bulk electronic band structure of PtLuSb with corresponding band character shown. The experimental Fermi level (blue), Ef-Exp, is ∼0.35 eV below the calculated Fermi level (red), Ef-Thry. A band inversion can be clearly seen at the bulk Γ point, where the orbital character of the Γ8 and Γ6 bands are inverted. This is in agreement with prior predictions11 that the TSS should connect these two bands.
