Low-energy V t2g orbital excitations in NdVO3
  The electronic structure of NdVO3, YVO3 has been investigated as a function of sample temperature using resonant inelastic soft x-ray scattering at the V L3-edge. Most of the observed spectral features are in good agreement with an atomic crystal-field multiplet model. However, a low energy feature is observed at ~0.4 eV that cannot be explained by crystal-field arguments. The resonant behaviour of this feature establishes it as due to excitations of the V t2g states. Moreover, this feature exhibits a strong sample temperature dependence, reaching maximum intensity in the orbitally-ordered phase of NdVO3, before becoming suppressed at low temperatures. This behaviour indicates that the origin of this feature is a collective orbital excitation, i.e. the bi-orbiton. 
J. Laverock, B. Chen, A. R. H. Preston, D. Newby Jr., L. F. J. Piper,   L. D. Tung, G. Balakrishnan, P.-A. Glans, J.-H. Guo,...
cond-mat.str-el