First-principles study of the electronic, magnetic, and crystal structure of perovskite molybdates

The molybdate oxides SrMoO3, PbMoO3, and LaMoO3 are a class of metallic perovskites that exhibit interesting properties including high mobility, and unusual resistivity behavior. We use first-principles methods based on density functional theory (DFT) to explore the electronic, crystal, and magnetic structure of these materials. To account for the electron correlations in the partially-filled Mo 4d shell, a local Hubbard U interaction is included. The value of U is estimated via the constrained random-phase approximation approach, and the dependence of the results on the choice of U are explored. For all materials, generalized-gradient approximation DFT+U predicts a metal with an orthorhombic, antiferromagnetic structure. For LaMoO3, the Pnma space group is the most stable, while for SrMoO3 and PbMoO3, the Imma and Pnma structures are close in energy. The R4+ octahedral rotations for SrMoO3 and PbMoO3 are found to be overestimated compared to the experimental low-temperature structure.