Equilibrium Stabilization of a Hidden Phase Like Metallic State in 1T-TaS2

Abstract: Electronic phases that lie outside the equilibrium ground state offer a route to explore competing configurations in correlated materials. In 1T-TaS2, ultrafast excitation accesses a metallic hidden phase that is distinct from the commensurate insulating ground state. Here we use angle-resolved photoemission spectroscopy to show that an equivalent electronic configuration is stabilized in exfoliated intermediate-thickness 1T-TaS2 flakes, where it persists up to room temperature before evolving through a different sequence of electronic transitions. This equilibrium hidden-phase-like state hosts a metallic band with finite Fermi-level spectral weight while retaining the characteristic hybridization gaps associated with the star-of-David band folding. These results establish a platform for controlling competing electronic states in layered materials, with implications for both quantum science and phase change technologies.