LDA+DMFT study for $L{a}_{1-x}S{r}_{x}Ti{O}_3$

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 $\mathrm{L}{\mathrm{a}}_{1-\mathrm{x}}\mathrm{S}{\mathrm{r}}_{\mathrm{x}}\mathrm{Ti}{\mathrm{O}}_3$ 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.

6 pages, 4 figures