Electride properties of ternary silicide and germanide of La and Ce

We present a theoretical study of the electronic, spectral, and magnetic properties of ternary $RE\mathrm{ScSi}$ and $RE\mathrm{ScGe}$ $(RE=\mathrm{La},\mathrm{Ce})$ compounds based on the $\mathrm{DFT}+\mathrm{DMFT}$ method combining Density Functional Theory with Dynamical Mean-Field Theory. In this work, we find that Ce-based compounds, similar to LaScSi, exhibit electride-like features. Our calculations reveal that not only silicide $RE\mathrm{ScSi}$ compounds, but also their germanide $RE\mathrm{ScGe}$ analogs, exhibit high interstitial density characteristic of electrides. Remarkably, we find that both rare-earth $5d$ and scandium $3d$ contribute electrons to the strongly localized interstitial electron density, which can be considered as an electride anion with pronounced $s$ symmetry. In addition, we show that the Ce-based compounds show effects of strong electronic correlations in the $4f$ shell of cerium ions and strongly resemble those of $\ensuremath{\gamma}\text{\ensuremath{-}}\mathrm{Ce}$.