Figure 1. Crystal structure, Brillouin zone and the cleaved surface of Cd₃As₂.

(a). Crystal structure of Cd₃As₂ with a body-centered tetragonal structure (Space group: I41cd). Such a unit cell can be viewed as a re-constructed 2 × 2 × 4 superstructure from a small sub-cell expanded in the bottom-left. The As ions form a face-centered cubic while the Cd ions fill 3/4 of the 8 tetragonal sites formed by the As ions. (b). The bulk Brillouin zone and projected (112) surface Brillouin zone used in the band structure calculations which corresponds to the smallest unit cell marked in the sub-cell as red arrows in (a). (c). The X-ray diffraction pattern of Cd₃As₂ powder taken with Cu Kα radiation (λ = 1.5418 Å). The measured spectrum (red squares) is compared with the calculated result (green line) from the structure refinement. It confirms the crystal structure with a space group I41cd; the lattice constants obtained are a = b = 12.6467 Å and c = 25.4428 Å. (d). X-ray diffraction pattern of a naturally cleaved surface of the Cd₃As₂ single crystal that indicates the (112) surface.