  Based on the first-principles density functional theory electronic structure
calculation, we investigate the possible phonon-mediated superconductivity in
arsenene, a two-dimensional buckled arsenic atomic sheet, under electron
doping. We find that the strong superconducting pairing interaction results
mainly from the $p_z$-like electrons of arsenic atoms and the $A_1$ phonon mode
around the $K$ point, and the superconducting transition temperature can be as
high as 30.8 K in the arsenene with 0.2 doped electrons per unit cell and 12\%
applied biaxial tensile strain. This transition temperature is about ten times
higher than that in the bulk arsenic under high pressure. It is also the
highest transition temperature that is predicted for electron-doped
two-dimensional elemental superconductors, including graphene, silicene,
phosphorene, and borophene.
