Insulator-Metal transition in the Doped 3d1 Transition Metal Oxide LaTiO3

TL;DR

This study uses advanced ab-initio methods to analyze the doping-induced insulator-metal transition in LaTiO3, revealing orbital order and a continuous transition consistent with experimental data, advancing understanding of Mott-Hubbard systems.

Contribution

It combines LDA+DMFT with realistic structural data to elucidate the electronic transition and orbital behavior in doped LaTiO3, providing new insights into its Mott-Hubbard nature.

Findings

Ferro-orbital order exists in the Mott insulating state.

Transition to paramagnetic metal occurs continuously with doping.

Quantitative agreement with photoemission data at 6% doping.

Abstract

The doping induced insulator-metal transition in $La_{1-x}Sr_{x}TiO_{3}$ is studied using the ab-initio LDA+DMFT method. Combining the LDA bandstructure for the actual, distorted structure found recently with multi-orbital 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.