Electron-doping-induced destabilization of the dimerized insulating state in monolayer IrTe₂

The ability to tune the electronic phases of two-dimensional (2D) materials through external perturbations provides a powerful route to engineer functional nanoscale systems. In particular, the ground state of monolayer (ML) 1T-IrTe₂ is highly sensitive to the interplay between local chemical bonding and global electronic topology, leading to a unique 2 × 1 dimerized insulating phase. Here, we present an angle-resolved photoemission study on the evolution of the electronic structure in ML IrTe₂ induced by in situ Rb adsorption. We find that Rb adsorption suppresses the 2 × 1 dimerized phase in ML IrTe₂, inducing a clear insulator-to-metal transition. This transition is characterized by a reconstruction of the band topology toward a bilayer-like metallic configuration. Combined with first-principles calculations, our results demonstrate that the collapse of the insulating state originates from Ir valence change and suppression of Fermi surface nesting-driven instabilities. Our findings establish ML IrTe₂ as a model system for investigating instability-driven phase control in 2D materials and highlight its potential for tunable electronic applications.