Anisotropy of Mott-Hubbard gap transitions due to spin and orbital   ordering in LaVO3 and YVO3
  Anisotropic optical spectra coupled with antiferromagnetic spin ordering (SO) and orbital ordering (OO) have been investigated for single crystals of LaVO_{3} and YVO_{3}. The orbital-dependent Mott-Hubbard gap transitions are observed around 2 eV. The transitions composed of the two peaks show distinct anisotropy and selection rules, reflecting the respective SO and OO patterns. The temperature dependence of the anisotropic transitions clearly indicates the SO/OO correlation and the evolution of the order parameters. 
Shigeki Miyasaka, Yoichi Okimoto and Yoshinori Tokura