Correlations induced orbital ordering and cooperative Jahn-Teller distortion in the paramagnetic insulator KCrF3
D. Novoselov+*, Dm. M. Korotin+, V. I. Anisimov+*
+Institute of Metal Physics, 620990 Yekaterinburg, Russia
*Ural Federal University, 620002 Yekaterinburg, Russia
Abstract
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.