Momentum dependence of orbital excitations in Mott-insulating titanates
arXiv:0908.2497 · doi:10.1103/PhysRevLett.103.107205
Abstract
High-resolution resonant inelastic x-ray scattering has been used to determine the momentum dependence of orbital excitations in Mott-insulating LaTiO$_3$ and YTiO$_3$ over a wide range of the Brillouin zone. The data are compared to calculations in the framework of lattice-driven and superexchange-driven orbital ordering models. A superexchange model in which the experimentally observed modes are attributed to two-orbiton excitations yields the best description of the data.
to appear in PRL