Hybridization-Gap Formation and Superconductivity in the Pressure-Induced Semimetallic Phase of the Excitonic Insulator Ta2NiSe5

The excitonic insulator Ta2NiSe5 experiences a first-order structural transition under pressure from rippled to flat layer-structure at Ps ∼ 3 GPa, which drives the system from an almost zero-gap s...