Strain and Spin-Orbit Coupling Induced Orbital-Ordering in Mott Insulator BaCrO3

Abstract

Using ab initio calculations, we have investigated an insulating tetragonally distorted perovskite BaCrO${}_3$ with a formal $3d^2$ configuration, the volume of which is apparently substantially enhanced by a strain due to SrTiO${}_3$ substrate. Inclusion of both correlation and spin-orbit coupling (SOC) effects leads to a metal-insulator transition and in-plane zigzag orbital-ordering (OO) of alternating singly filled $d_{xz}+i{d}_{yz}$ and $d_{xz}-i{d}_{yz}$ orbitals, which results in a large orbital moment $M_L$ ~ -0.78 ${\mu }_B$ antialigned to the spin moment $M_S$ ~ $2|M_L|$ in Cr ions. Remarkably, this ordering also induces a considerable $M_L$ for apical oxygens. Our findings show metal-insulator and OO transitions, driven by an interplay among strain, correlation, and SOC, which is uncommon in 3d systems.

6 pages, 5 figures

References in corpus (10)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Orbital order and possible superconductivity in LaNiO3/LaMO3 superlattices
• Structural, orbital, and magnetic order in vanadium spinels
• Nature of magnetism in Ca${}_3$Co${}_2$O${}_6$
• CaCrO3: an anomalous antiferromagnetic metallic oxide
• Orbital order in ZnV${}_2$O${}_4$
• Orbital-quenching-induced magnetism in Ba_2NaOsO_6
• Orbital-ordering driven structural distortion in metallic SrCrO3
• Disproportionation Transition at Critical Interaction Strength: Na${}_{1/2}$CoO${}_2$