Semiconductor-to-metal transition of Bi₂Se₃ under high pressure

Pressure-induced electrical transport properties of Bi₂Se ₃, including Hall coefficient, carrier concentration, mobility, and electrical resistivity, have been investigated under pressure up to 29.8 GPa by in situ Hall-effect measurements. The results indicate that the structural and electronic phase transitions of Bi₂Se₃ induce discontinuous changes in these electrical parameters. The significant anomaly in Hall coefficient at 5 GPa reveals an electronic topological transition deriving from the topological change of the band extremum (Van Hove singularity). Additionally, electrical resistivity measurements under variable temperatures show that the insulating state of Bi₂Se₃ becomes increasingly stable with an increase of pressure below 9.7 GPa. But above 9.7 GPa, Bi₂Se₃ enters into a fully metallic state. As the metallization occurs, the topological property of Bi₂Se₃ disappears.