Correlation effects in electronic structure of actinide monochalcogenides

We have implemented a technique for realistic electronic structure calculations of $f$-electron systems with moderately strong correlations. The technique is based on the dynamical mean-field theory with a perturbative treatment of effective quantum impurity problem in a spin-polarized version of the $T$ matrix combined with the fluctuating exchange approximation (SPTF). The present many-body approach properly includes the effects of strong spin-orbit coupling. We have used this technique for the dynamic mean-field theory (DMFT) calculations of ferromagnetic (USe, UTe) and nonmagnetic (PuSe, PuTe) actinide chalcogenides. In the static limit, the local-density approximation $\left(\mathrm{LDA}\right)+\mathrm{U}$ method correctly reproduces the ground-state magnetic properties of these compounds, but fails to describe their spectral properties. Dynamical correlation effects drastically improve the agreement between theoretical densities of states and experimental photoemission spectra for the systems under consideration.

Figure 1

(a) Antisymmetric vertex (7). (b) The particle-hole contribution to the generating functional.

Figure 2

The imaginary part of $\Sigma \left(i\omega \right)$ calculated with (solid line) and without (dashed line) the asymptotical tail for a two-band model on the Bethe lattice for $\beta =\frac{1}{64}$, $U=2$, and bandwidth $W=2$ (in arbitrary units).

Figure 3

(Color online) The total DOS (solid line) as well as the partial DOS for actinide (dashed line) and chalcogen (dot-dashed line) atoms obtained by the $\mathrm{LDA}+U$ method. The thick solid line is the experimental photoemission spectra (in arbitrary units) for UTe, PuTe (Ref. 40), and PuSe (Ref. 39).

Figure 4

(Color online) The total DOS (solid line) as well as the partial DOS for actinide (dashed line) and chalcogen (dot-dashed line) atoms obtained by the DMFT calculations with the $\mathrm{SPTF}+\mathrm{SO}$ quantum impurity solver. The thick solid line is the experimental photoemission spectra (in arbitrary units) for (U,Pu)Te (Ref. 40) and PuSe (Ref. 39).