Hidden orbital fluctuations in the solid solution Y1-xLaxTiO3 (x<0.2)

The electronic properties of Y1-xLaxTiO3 (x < 0.2) solid solution are described using the state-of-the-art LDA+DMFT method. It is shown that both structural distortions and multiorbital electron interactions are key aspects towards orbital polarization. Our results for stoichiometric YTiO3 explain various correlated features seen in one- and two-particle spectra of the paramagnetic insulating state. We also clarify the evolution of this correlated electronic state in the limit of small x. In agreement with optical experiments, we show that substitution of La for Y strongly renormalizes the one-particle spectra due to large transfer of spectral weight upon small perturbations.