Electronic and magnetic structure of $R{\text{ScO}}_3$ ($R=\text{Sm}$,Gd,Dy) from x-ray spectroscopies and first-principles calculations

The electronic structures of ${\text{SmScO}}_3$, ${\text{GdScO}}_3$, and ${\text{DyScO}}_3$ are investigated by means of x-ray photoelectron spectroscopy, x-ray emission spectroscopy (XES), and x-ray absorption spectroscopy (XAS). A strong hybridization between $\text{Sc}3d$ and $\text{O}2p$ is found, and a contribution of the rare-earth $5d$ states to this hybridization is not excluded. The band gaps of the compounds are determined by combining XES and XAS measurements. For ${\text{SmScO}}_3$, ${\text{GdScO}}_3$, and ${\text{DyScO}}_3$ the band gaps were determined to be 5.6, 5.8, and 5.9 eV, respectively. Magnetization versus temperature measurements reveal antiferromagnetic coupling at 2.96 $\left({\text{SmScO}}_3\right)$, 2.61 $\left({\text{GdScO}}_3\right)$, and 3.10 K $\left({\text{DyScO}}_3\right)$. For ${\text{DyScO}}_3$ a Rietveld refinement of a 2 K neutron-diffraction data set gives the spin arrangement of Dy in the $Pbnm$ structure (Shubnikov group: $P{b}^{\prime }{n}^{\prime }{m}^{\prime }$).

Figure 1

$M\text{−}T$ curves for ${\text{SmScO}}_3$, ${\text{GdScO}}_3$, and ${\text{DyScO}}_3$. The measurement was performed under an applied flux of ${\mu }_{0}H=0.5\text{T}$ after cooling from 300 K in the same field. The magnification factor is indicated. The inset shows the high-temperature range for ${\text{DyScO}}_3$. The constant $M$ offset at 300 K has been subtracted.

Figure 2

(Color online) Neutron-diffraction and crystal (magnetic) structures of ${\text{DyScO}}_3$. Results of the Rietveld refinement of the (a) 2 and (b) 300 K neutron powder diffraction data of ${\text{DyScO}}_3$. The crystal and the magnetic structure (arrangement of arrows representing magnetic moments at Dy sites) is also shown.

Figure 3

Selected partial DOS in ${\text{SmScO}}_3$, ${\text{GdScO}}_3$, and ${\text{DyScO}}_3$. The zero of energy scale is set to the top of the valence band. For $\text{Sc}3d$ and $\text{O}2p$, only one component of spin-resolved DOS is shown, which is indistinguishable from the other. Sc site is nonmagnetic by symmetry. $\text{O}2p$ stands for a mean value (per atom) over four inequivalent oxygen sites.

Figure 4

(Color online) XPS valence bands (black thick lines) of ${\text{SmScO}}_3$ (top), ${\text{GdScO}}_3$ (middle), and ${\text{DyScO}}_3$ (bottom). The convoluted and weighted tDOS with different $U$ values and the corresponding nonconvoluted tDOS are shown below the XPS. The calculations are shifted by $-2.5\text{eV}$ for comparison with experiment.

Figure 5

(Color online) XPS valence bands and experimental $R{M}_{4,5}$, $\text{O}K$, and $\text{Sc}{L}_{2,3}$ XE spectra (thick lines). The corresponding calculated partial DOSs (thin lines) are also shown and are shifted by $-2.5\text{eV}$ for comparison with experiment. Calculations of $R$ metals in the Russel-Saunders spin-orbit coupling scheme from Lang et al.[38] are plotted below the $R{\text{ScO}}_3$ XPS spectra.

Figure 6

(Color online) $\text{O}K$ XAS (blue) and XES (red) of ${\text{SmScO}}_3$, ${\text{GdScO}}_3$, and ${\text{DyScO}}_3$. $\text{LDA}+U$ calculations below experimental data were convoluted with 0.7 (XES) and 0.4 eV (XAS) Gaussian for experimental broadening. The calculated unoccupied states are shifted upwards by 1.4 eV for ${\text{SmScO}}_3$, 1.6 eV for ${\text{GdScO}}_3$, and 1.5 eV for ${\text{DyScO}}_3$.