Correlations induced orbital ordering and cooperative Jahn-Teller distortion in the paramagnetic insulator KCrF$_3$

TL;DR

This study uses advanced computational methods to reveal that orbital ordering and Jahn-Teller distortions in KCrF$_3$ originate from electronic interactions, independent of magnetic order, providing new insights into its structural properties.

Contribution

The paper demonstrates that orbital ordering in KCrF$_3$ arises from electronic effects, independent of magnetic ordering, using DFT+DMFT simulations of the paramagnetic phase.

Findings

Orbital ordering exists even without magnetic order.

Jahn-Teller distortions are driven by electronic interactions.

The approach accurately describes the paramagnetic phase.

Abstract

We investigate the origin of the orbital ordering in the paramagnetic phase of KCrF$_3$. All previous studies described structural parameters of the paramagnetic phase using a magnetic ordering in the compound. Our simulations of real paramagnetic KCrF$_3$ were performed within an approach combining density functional theory and dynamical mean field theory (DFT+DMFT). As a result, it was found that the experimentally observed cooperative Jahn-Teller effect is successfully described in a lattice relaxation calculation for structure without any long-range magnetic ordering. It is established that the existence of the orbital ordering even in undistorted perovskite structure clearly confirms the electronic origin of the orbital ordering in KCrF$_3$.