Dynamic octahedral fluctuations and the effects on orbital ordering in YTiO3...

YTiO3 is revisited to investigate the influence of local lattice dynamics on orbital ordering using inelastic neutron scattering. Orbital order survives well above the ferromagnetic transition, into the paramagnetic state, but what eventually leads to disorder is not well understood. By probing the local lattice dynamics via the dynamic pair density function analysis, it is found that local fluctuations associated with octahedral tilting and rotational modes and Y displacements persist up to 60 meV. The local fluctuations exhibit a temperature dependence that may lead to the suppression of the Ti orbital overlap leading to a temperature dependent orbital disorder.