Magnetic neutron scattering study of YVO3: Evidence for an orbital   Peierls state
  Neutron spectroscopy has revealed a highly unusual magnetic structure and dynamics in YVO$_3$, an insulating pseudocubic perovskite that undergoes a series of temperature induced phase transitions between states with different spin and orbital ordering patterns. A good description of the neutron data is obtained by a theoretical analysis of the spin and orbital correlations of a realistic one-dimensional model. This leads to the tentative identification of one of the phases of YVO$_3$ with the ``orbital Peierls state'', a theoretically proposed many-body state comprised of orbital singlet bonds. 
C. Ulrich, G. Khaliullin, J. Sirker, M. Reehuis, M. Ohl, S. Miyasaka,   Y. Tokura, B. Keimer