Electronic structure studies of the perovskite oxides La1-xCexMnO3 from first-principles calculations

Ce-doped LaMnO3 has complicated physical properties, such as unclear valence states of Ce and Mn ions, ferromagnetism paramagnetism and metal-insulator transitions, and multiphase coexistence. To explore the ground-state properties of single-phase La1-xCexMnO3 and obtain better understanding of the complicated physical properties of the multiphase system, the electronic and magnetic structures of La1-xCexMnO3 are investigated by using the first principle calculations. The results show that single phase La1-xCexMnO3 is neither a hole-doped nor an electron-doped compound. The valence states of Ce and Mn ions are predicted to be trivalent in an ionic picture. Trivalent Mn ions energetically favor an A-type antiferromagnetic ordering and insulating band structure. In comparison with the experimental studies, it is concluded that over-oxygenation and multiphase coexistence in experiments switch the ground state from an antiferromagnetic insulator to a ferromagnetic half-metal. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim