Electron-phonon properties, structural stability, and superconductivity of doped antimonene

Abstract

Antimonene is a recently discovered two-dimensional semiconductor with exceptional environmental stability, high carrier mobility, and strong spin-orbit interactions. In combination with an electric field, the latter provides an additional degree of control over the material's properties because of induced spin splitting. Here, we report on a computational study of electron-phonon coupling and superconductivity in n- and p-doped antimonene, where we pay special attention on the effect of the perpendicular electric field. The range of accessible hole concentrations is significantly limited by the dynamical instability, associated with strong Fermi-surface nesting. At the same time, we find that in the case of electron-doping antimonene remains stable and can be turned into a state with strong electron-phonon coupling, with the mass enhancement factor λ of up to 2.3 at realistic charge carrier concentrations. In this regime, antimonene is expected to be a superconductor with the critical temperature of ≈16 K. Application of bias voltage leads to a considerable modification of the electronic structure, affecting the electron-phonon coupling in antimonene. While these effects are less obvious in the case of electron-doping, the field effect in hole-doped antimonene results in a considerable variation of the critical temperature, depending on bias voltage. © 2019 American Physical Society.