Pressure-modulated lattice structural evolution in TiS 2 .

Titanium disulfide (TiS 2 ) has drawn considerable attention in materials, physics, and chemistry thanks to its potential applications in batteries, supercapatteries and thermoelectric devices. However, the simplified and controlled synthesis of high-quality TiS 2 remains a great challenge. In this study, a straightforward widely accessible approach to the one-step chemical vapor transport (CVT) process is presented. Meanwhile, combining high-pressure (HP) Raman spectroscopy measurements and first-principles calculations, the pressure-induced phase transition of TiS 2 from P 3̄ m 1 phase (phase I) to C 2/ m phase (phase II) at 16.0 GPa and then to P 6̄2 m phase (phase III) at 32.4 GPa was disclosed. The discovery of HP being within the Weyl semi-metallic phase represents a significant advancement towards understanding the electronic topological states, discovering new physical phenomena, developing new electronic devices, and gaining insight into the properties of elementary particles.