Growth and characterization of large weak topological insulator Bi2TeI single crystal by Bismuth self-flux method

• Single crystal growth of weak topological insulator Bi2TeI compound.
• Study on the X-ray diffraction of Bi2TeI single crystal.
• Transport properties of Bi2TeI crystal (4-probe/Hall effect measurements).

Two dimensional (2D) topological insulators (TIs) with a quantum spin Hall (QSH) effect feature edge states (ESs) that are topologically protected from backscattering. Bi2TeI with 2D Bismuth bilayer is one of the representative compounds of weak topological insulator. However, nobody has prepared a high quality single crystal with a millimeter size so far. Here, we have successfully synthesized a large single crystal sized up to “millimeter (~5×5 mm2)” using the Bismuth self-flux method. And we also found its giant anisotropy transport behavior in Bi2TeI of a 2D TI constructed from nontrivial Bi bilayers (Quantum Spin Hall phase) capped by a trivial Te–Bi–I layer.