Dynamics of orbital degree of freedom in transition-metal oxides Original Research Article

The collective excitation in the orbital degree of freedom termed orbital wave is studied in the orbital ordered transition-metal oxides, in particular, in LaMnO3. Symmetry, dispersion and energy gap of this excitation are examined by the group theoretical analyses and the linear spin-wave theory. The cross-section of the Raman scattering from the orbital wave is calculated and is compared with the recent experimental results.