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

TL;DR

This study uses first-principles density functional theory to investigate the electronic, magnetic, and crystal structures of perovskite molybdates, accounting for electron correlations with Hubbard U, and compares theoretical predictions with experimental data.

Contribution

It provides a detailed first-principles analysis of the structural and electronic properties of SrMoO$_3$, PbMoO$_3$, and LaMoO$_3$, including the effects of electron correlations and structural stability.

Findings

All materials are predicted to be metallic with orthorhombic, antiferromagnetic structures.

LaMoO$_3$ favors the Pnma space group, while SrMoO$_3$ and PbMoO$_3$ are close in energy for Imma and Pnma.

The calculated octahedral rotations are overestimated compared to experimental low-temperature structures.

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.