Insulator-metal transition in the doped 3d1 transition metal oxide LaTiO3

The doping induced insulator-metal transition in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Ti}{\mathrm{O}}_{3}$ is studied using the ab initio local density approximation (LDA) and DMFT method. Combining the LDA bandstructure for the actual, distorted structure found recently with multiorbital DMFT to treat electronic correlations, we find (i) ferro-orbital order in the Mott insulating state without orbital degeneracy, (ii) a continuous filling induced transition to the paramagnetic metal (PM) with $x$, and (iii) excellent quantitative agreement with published photoemission data for the case of 6% doping. Our results imply that this system can be described as a Mott-Hubbard system without orbital (liquid) degeneracy.