Pressure-induced metallization and Lifshitz transition in quasi-one-dimensional TiSe₃ single crystal

The transition metal trichalcogenides (TMTs) with quasi-one-dimensional (quasi-1D) layered crystal structure represent a unique platform to explore intriguing physical properties. Herein, we report the successful growth of a new TMT TiSe₃ single crystal by using a high-pressure and high-temperature technique. The crystal structure of TiSe₃ was determined by measuring the single-crystal x-ray diffraction and selected area electron diffraction. The 1D chain-like structure along the b-axis is formed by the TiSe₆ prisms which share their tops and bottoms with each other. TiSe₃ is a narrow band gap semiconductor with electron-type carriers under ambient conditions identified by the electrical and Hall effect measurements. It exhibits a pressure-induced semiconductor-to-metal transition around 4 GPa. As the pressure further increases to ∼ 6 GPa, a pressure-induced Lifshitz transition occurs, as indicated by the electrical transport measurements, high-pressure crystal structure characterizations, and electronic band structure calculations.