Abstract
We present a theory of the collective orbital excitation termed orbital wave in perovskite titanates and vanadates with the triply degenerate orbitals. The dispersion relations of the orbital waves for the orbital-ordered and are examined in the effective spin-orbital coupled Hamiltonians associated with the Jahn-Teller type couplings. We propose possible scattering processes for the Raman and inelastic neutron scatterings from the orbital wave and calculate the scattering spectra for titanates and vanadates. It is found that both the excitation spectra and the observation methods of the orbital wave are distinct qualitatively from those for the orbital-ordered systems.
- Received 28 July 2003
DOI:https://doi.org/10.1103/PhysRevB.69.075118
©2004 American Physical Society