Correlations induced orbital ordering and cooperative Jahn-Teller distortion in the paramagnetic insulator KCrF3

摘要

We investigate the origin of the orbital ordering in the paramagnetic phase of KCrF3. All previous studies described structural parameters of the paramagnetic phase using a magnetic ordering in the compound. Our simulations of real paramagnetic KCrF3 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 KCrF3.