Exploration of the novel structures and electronic properties for Nd3+ doped CaTiO3

Abstract

Abstract Rare-earth neodymium ions (Nd3+) doped CaTiO3 crystal shows excellent light-emitting properties which give rise to the development of new-generation laser devices. However, the structural evolutions of the trivalent Nd3+ doped CaTiO3 (CaTiO3:Nd) crystal are still not clear. Herein, we report a systematic first-principles study on the geometrical structures and electronic properties of CaTiO3:Nd. Based on the crystal structure analysis by particle swarm optimization (CALYPSO) method combined with density functional theory, we uncover a novel layered grid structure with Pm space group. The Ca2+ ion in the host crystal is replaced by the Nd3+ ion. The simulated XRD spectrums match fairly well with the experimental data, which demonstrating the validity of the obtained ground state structure. The calculated band structures manifest that the conduction band pass through the Fermi level, suggesting a conductive character of CaTiO3:Nd. The results of density of states (DOS) demonstrate that the impurity Nd3+ ions can trigger a phase transition of CaTiO3 from semiconductor to conductor. The analysis of electron localization function (ELF) for CaTiO3:Nd indicates that the interaction between Ca-O is mainly ionic bond. These results could provide significant insights for exploring new laser materials.