First Principles Study of the Electronic and Magnetic Properties of Ce Doped SrMnO3

The electronic and magnetic properties of Ce doped SrMnO3 have been investigated using the pseudo-potential plane wave method within the generalized gradient approximation method by first principles. The different Mn-O bond lengths indicate that there is a strong Jahn-Teller distortion of the MnO6 octahedron, which associates with a structural phase transition from cubic symmetry (Pm (3) over barm) to tetragonal symmetry (I4/mcm), and the Jahn-Teller ordering stabilizes a chain like (C-type) antiferromagnetic ground state. The electronic structures indicate that SrMnO3 and Sr1-xCexMnO3 (x=0.125 and 0.25) are semiconductor and metallic, respectively. The doping of SrMnO3 with cerium induces simultaneously a decrease in the electrical resistivity, which can be attributed to the formation of Mn3+ as a. result of charge compensation. The density of states and charge density map present that hybridization exists between some of O bands with those of Mn and Ce bands, the bonding between Sr and O is mainly ionic. Density of states and magnetic moment calculations show that the formal valence state of the Ce ion is trivalence.