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

Abstract

The molybdate oxides SrMoO${}_3$, PbMoO${}_3$, and LaMoO${}_3$ 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 to explore the electronic, crystal, and magnetic structure of these materials. In order 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, GGA+$U$ predicts a metal with an orthorhombic, antiferromagnetic structure. For LaMoO${}_3$, the $Pnma$ space group is the most stable, while for SrMoO${}_3$ and PbMoO${}_3$, the $Imma$ and $Pnma$ structures are close in energy. The $R_4^{+}$ octahedral rotations for SrMoO${}_3$ and PbMoO${}_3$ are found to be overestimated compared to the experimental low-temperature structure.

14 pages, 8 figures