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 electric field, the latter provides an additional degree of control over the materials' 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 a 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 case of electron-doping antimonene remains stable and can be turned into a state with strong electron-phonon coupling, with the mass enhancement factor $\lambda$ 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 $\sim$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 case of electron-doping, field-effect in hole-doped antimonene results in a considerable variation of the critical temperature depending on bias voltage.