First-principles study of electronic structure, magnetic and optical properties of Mg-doped CeO2 (1 1 1) surface

Abstract

The electronic structure, magnetic and optical properties of Mg-doped CeO2 (1 1 1) surface have been investigated by first-principles calculations. In this paper, the doping case is actively favorable to process under O-rich conditions than under Ce-rich conditions. The distortion of doping systems of Mg replacing Ce of surface is larger than that of subsurface. The covalent character is getting weaker and the ionic character is gradually obvious for MgO bond from surface to subsurface doping. The results show that the existence of defect states with O 2p orbital character makes spin splitting, causing the local and scattered magnetic moments for surface and subsurface doping of Ce, respectively. And the 9 and 12 atomic layers doping systems exhibit magnetic ground states with different magnetic moments. In particular, the calculated Curie temperature (about 434, 483, 1200 K) is higher than room temperature (RT), therefore, the theoretical results showed that Mg-doped CeO2 (1 1 1) thin films would can be obtained stable room temperature ferromagnetism (RTFM), which is beneficial to practical application. In addition, the optical properties show that all doped systems are capable of enhancing effective absorption of visible and near-infrared light.