Abstract
The interactions between orbitals in neighboring sites are investigated in by taking into account virtual exchange of electrons and phonons. The spin and orbital ordering temperatures and the spin-wave dispersion relation are calculated. We find that the orbital ordering is mainly caused by the electronic interactions and that the Jahn-Teller coupling is much smaller than that reported previously. We propose that the elastic constant shows a characteristic change at the Néel temperature by the spin and orbital couplings and the higher-order Jahn-Teller coupling.
- Received 24 October 2001
DOI:https://doi.org/10.1103/PhysRevB.65.144403
©2002 American Physical Society