Figure 1

(a) Crystal structure of the C1_b-type half-Heusler NiZrSn alloys. The shaded plane indicates the (110) mirror plane. The coordinates in the figure are the relative coordinates of Ni₃₆Zr₃₂Sn₃₂ in the supercell. (b) Atomic coordinates of the various half-Heusler structures and their defect models: perfect crystal structure of the half-Heusler alloy (Model 1); an interstitial Ni disorder at one of the vacancy sites (Model 2); the atoms around the interstitial Ni disorder that are structurally relaxed to the optimal atomic position (Model 3). The arrows indicate the direction from the equilibrium position to the relaxed position.