First-principles study on the doping effects of La on the structural, electronic and optical properties of MgO

Abstract

The structural, electronic and optical properties of pure MgO and La-doped MgO were investigated by first-principles study based on density functional theory (DFT). The good agreement of the calculated lattice parameters of MgO with experimental and other theoretical data was obtained. It was found that the calculated band gap of MgO using LDA functional is 4.756 eV and the presence of La impurity in MgO decreases the band gap to 1.812 eV. The high contribution of La 5d state was found at conduction band while the main peak of valence band is represented by O 2p state. The optical properties for the absorption coefficient with and without scissor operator (SO) were also presented and compared with the optical absorption spectra from experimental data. The red-shift of the absorption was obtained which show that the La doping can extend the absorption range in MgO. These findings would be useful for understanding the behavior of MgO and La-doped MgO for promising material in photocatalyst application.