Acceptor-Enhanced Insulator-to-Metal Transition in 2D Si ₂ Te ₃ from First-Principles Calculations

Controlling the insulator-to-metal transition (IMT) in Si 2 Te 3 is a key step toward high-performance applications enabled by the phase transition in Si-compatible 2D materials. In this study, we present first-principles investigations of how acceptor doping can modulate the IMT in Si 2 Te 3 . Using density functional theory calculations, we examined the effects of As, P, and B dopants on the relative thermodynamic stability and kinetic barriers associated with Si dimer dissociation. All three dopants preferentially occupy substitutional sites, and at these sites, they can act as acceptors. These acceptor dopants facilitate the transition by stabilizing the metallic phase and reducing the kinetic barriers. The degree of stabilization follows the order As < P < B, indicating that the acceptors contribute to the IMT not only through hole doping but also through an additional structural effect. This effect originates from the smaller dopants being more favorably accommodated in the compact metallic lattice, leading to lower formation energies and, thus, enhancing the stability of the metallic phase. These results highlight a doping strategy to tailor the IMT behavior of Si 2 Te 3 and suggest its potential for use in IMT-based device applications.