Fig. 2: Crystal structures of the ZrTe5 monolayers.
From: Realization of monolayer ZrTe5 topological insulators with wide band gaps
a Top and side views of the crystal structure of bulk ZrTe5, namely, the ‘21’ configuration. The labels ‘2’ indicate the ZrTe3 prims with the Te dimer on top, and labels ‘1’ indicate the ZrTe3 prims with the apical Te atom on top. b Atomically resolved topographic image (10 × 10 nm2) taken on the surface of a bulk ZrTe5. U = + 350 mV, It = 130 pA. c, d Top and side views of the crystal structures of phases I (‘221’) and II (‘2211’), respectively. The black parallelogram in (c) and rectangle in (d) represent the primitive unit cells of phases I and II, respectively. The green rectangle in (c) marks the extended orthorhombic cell that is twice in size of the black parallelogram cell. The angle between the a and c axes in the primitive unit cell is labeled as θ. e Comparison between the experimental STM image (left panel, U = + 300 mV) and simulated image (right panel) for phase I. f Same as (e) but for phase II. The experimental STM image was obtained at U = − 500 mV.
