Effects of rare earth adsorption on electronic structure and optical properties in β-Si₃N₄ ceramics from first principles

Electronic structure and optical properties of silicon nitride adsorbed by rare earths are explored by density functional theory. The fully relaxed structural parameters are found to be in good agreement with experimental data. Covalent character of polar covalent bonds by rare earth adsorption is in the order of Gd, Yb, Sc, Sm, La and Lu, which is verified by population values. Gd, Yb, Sc and La adsorption systems may exhibit longer life in applications as dielectric materials in the low energy regions because of the low static dielectric constant and loss, as well as transparent type characteristic exhibited in visible regions.