Orbital Kondo Effect in ${\mathrm{C}\mathrm{r}\mathrm{O}}_2$: A Combined Local-Spin-Density-Approximation Dynamical-Mean-Field-Theory Study

Motivated by a collection of experimental results indicating the strongly correlated nature of the ferromagnetic metallic state of ${\mathrm{C}\mathrm{r}\mathrm{O}}_2$, we present results based on a combination of the actual band structure with dynamical-mean-field theory for the multiorbital case. In striking contrast to $\mathrm{L}\mathrm{S}\mathrm{D}\mathrm{A}(+U)$ and model many-body approaches, much better semiquantitative agreement with (i) recent photoemission results, (ii) domain of applicability of the half-metal concept, and (iii) thermodynamic and dc transport data is obtained within a single picture. Our approach has broad applications for the detailed first-principles investigation of other transition metal oxide-based half-metallic ferromagnets.

Figure 1

$t_{2g}$ $\mathrm{L}\mathrm{S}\mathrm{D}\mathrm{A}+U$ density of states per formula unit for both spin channels obtained from 3, Figs. 3 (spin-down) and 4 (spin-up).

Figure 2

$\mathrm{L}\mathrm{S}\mathrm{D}\mathrm{A}+\mathrm{D}\mathrm{M}\mathrm{F}\mathrm{T}$ partial ($xy$ and $\alpha =yz\pm zx$) and total density of states for the Cr $t_{2g}$ orbitals for $U^{\prime }=3.0\mathrm{e}\mathrm{V}$.

Figure 3

The integrated photoemission line shapes for the spin-up channel within $\mathrm{L}\mathrm{S}\mathrm{D}\mathrm{A}+\mathrm{D}\mathrm{M}\mathrm{F}\mathrm{T}$ for $U^{\prime }=3.0\mathrm{e}\mathrm{V}$ (solid line) and $\mathrm{L}\mathrm{S}\mathrm{D}\mathrm{A}+U$ (dashed line).