Optical absorption in monolayer SnO2

Abstract

Since the discovery of graphene, considerable research efforts have focused on understanding the properties of other two-dimensional materials. Herein, based on ab initio many-body calculations, we report the optical properties of monolayer ${\mathrm{SnO}}_{2}$. First, we apply the first-principles density functional theory, self-consistent quasiparticle Green's function, and screened Coulomb method to determine the quasiparticle electronic structure. Second, we solve the Bethe-Salpeter equation to obtain the absorption spectra. The quasiparticle band structure reveals an indirect quasiparticle band gap. The absorption spectra show that the direct optical excitation is characterized by an optical band gap of $\ensuremath{\sim}5.36$ eV, which is dominated by strongly bound excitons.