Weyl Semimetal Phase in 2D Tellurium Under High Pressure

Relativistic Weyl fermion quasiparticles in Weyl semimetal bring the electron’s chirality degree of freedom into the electrical transport and give rise to various exotic phenomena. A topological phase transition from topological trivial phase to topological non-trivial phase offers a route to controllable topological electronic devices. Here, we report the Weyl semimetal phase in hydrothermally grown two-dimensional (2D) Tellurium (Te) induced by pressure (up to 2.47 GPa). The highly tunable chemical potential in 2D Te provides a comprehensive understanding of the pressure-dependent electron band structure. The pressure-induced insulator to metal transition, two-carrier transport, and the non-trivial π phase shift in quantum oscillations are observed in the 2D Te Weyl semimetal phase. Our work demonstrates the pressure-induced bandgap closing in inversion asymmetric narrow bandgap semiconductors and opens the door for the electronic transport study on the topological phase transition process.