LDA+DMFT study for $La_{1-x}Sr_{x}TiO_{3}$

TL;DR

This paper employs LDA+DMFT with NCA to investigate the electronic structure of doped Mott insulator La_{1-x}Sr_xTiO_3, revealing Hubbard bands and Kondo resonance consistent with experimental spectra.

Contribution

It introduces a novel LDA+DMFT scheme combined with NCA for studying strongly correlated materials, capturing multiplet structures and providing first-principles insights.

Findings

Identification of lower and upper Hubbard bands in spectra

Observation of Kondo resonance near Fermi level

Qualitative agreement with experimental photoemission data

Abstract

The dynamical mean-field theory together with the non-crossing approximation is used to set up a novel scheme to study the electronic structure of strongly correlated electron systems. The non-interacting band structure is obtained from a density functional calculation within the local density approximation. With this method the doped Mott insulator $\rm La_{1-x}Sr_x Ti O_3$ is studied. Starting from first-principle calculations for a cubic and an orthorhombic system we determined the one-particle spectrum. Both one-particle spectra show a lower Hubbard band (seen as $d^1 \to d^o$ transitions in photo emission experiments), a Kondo resonance near the Fermi energy and the upper Hubbard band ($d^1\to d^2$ transitions in an inverse photoemission experiment). The upper Hubbard band develops a multipeak structure, a consequence of the consideration of all local two-particle correlations, which leads to the full multiplet structure in the atomic limit. The calculation for the orthorhombic system shows qualitative good agreement when compared with experimental photoemission spectra.