Electronic and optical properties of ultrathin cerium dioxide: A many-body GW-BSE investigation

Abstract

Ultrathin CeO2 shows enormous potential as promising optical, catalytic, and electronic materials. However, accurate calculations of the basic structural, electronic, and optical properties of ceria in the ultrathin limit have been lacking by far. In this work, structural, electronic, and optical properties of ultrathin CeO2 are investigated. Phonon dispersion calculations are performed for ultrathin CeO2 to justify its dynamic stability. Band structures and density of states of ultrathin CeO2 are calculated by the density functional theory. After the GW correction, the quasiparticle band energies of ultrathin CeO2 from monolayer to tetralayer are predicted. Band edge positions of ultrathin CeO2 are also determined, and their thickness dependence is displayed for tunable photocatalytic applications. The optical properties of monolayer CeO2 have been calculated by solving the Bethe-Salpeter equation and eliminating the ambiguity introduced by the vacuum layer added in the supercell. Our calculations predict that monolayer CeO2 has great in-plane optical performance in the ultra-violet region and can be tuned for further photocatalytic and optoelectronic applications.