(color online) Frequency dependence of the Eliashberg spectral function α 2 F ( ω ) and λ ( ω ) for four electron-doped arsenenes: (a) 0.1 e/cell. (b) 0.2 e/cell. (c) 0.3 e/cell. (d) 0.4 e/cell. λ ( ω ) is defined by 2 ∫ 0 ω ( 1 / ω ′ ) α 2 F ( ω ′ ) d ω ′ .