Cooperative effects of Jahn-Teller distortion, magnetism, and Hund's coupling in the insulating phase of BaCrO3

We employ a combination of density functional theory and dynamical mean-field theory to investigate the electronic structure of the recently synthesized insulator BaCrO3. Our calculations show that Hund's coupling is responsible for strong correlation effects, which are however not sufficient to turn the system insulating without breaking any symmetry. The Hund's correlated metal is however unstable with respect to orbital ordering, which indeed makes the system insulating. The orbitally ordered insulator favors Jahn-Teller distortions and a secondary magnetic ordering.