Electronic topological transition and semiconductor-to-metal conversion of Bi₂Te₃ under high pressure

Accurate high pressure in situ Hall-effect and temperature dependent electrical resistivity measurements have been carried out on Bi ₂Te₃, a topological insulator. The pressure dependent electrical resistivity, Hall coefficient, carrier concentration, and mobility show the abnormal inflection points at 8, 12, and 17.8 GPa, indicating that the pressure-induced structural phase transitions of Bi₂Te₃ can result in a series of changes in the carrier transport behavior. In addition, the Hall coefficient shows a significant discontinuous change at 4 GPa, which is caused by the electronic topological transition. A sign inversion of Hall coefficient from positive to negative is found around 8 GPa. Furthermore, the temperature dependent electrical resistivity shows that the sample undergoes a semiconductor-to-metal conversion around 9.2 GPa, indicating that the insulating gap of Bi₂Te₃ becomes closed at this pressure. As the metallization occurs in the sample, the topological property of Bi₂Te₃ disappears.