Pressure Induced Semiconductor-Semimetal Transition in WSe₂

A pressure induced semiconductor-semimetal phase transition on tungsten diselenide has been studied using in situ electrical resistivity measurement and first-principles calculation under high pressure. The experimental results indicate that the phase transition takes place at 38.1 GPa. The first-principles calculations performed by CASTEP code based on the density functional theory illustrate that the indirect band gap of WSe 2 vanishes at 35 GPa, which results in an isostructural phase transition from semiconductor to semimetal in WSe 2 . According to the pressure dependence of partial density of states, the semimetallic character of WSe 2 is mainly caused by W−Se covalent bonding rather than van der Waals bonding.