Electronic structure of Tb0.5Sr0.5MnO3

We study the electronic structure of single-crystal ${\mathrm{Tb}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$, a non-charge-ordered mixed-valent semiconductor which exhibits glassy magnetic ground state. use techniques soft x-ray photoemission, hard absorption, and resonant photoemission spectroscopy to investigate occupied unoccupied states ${\mathrm{Tb}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$. Core level absorption allow us determine valence Tb, Sr, Mn ions in Model charge transfer multiplet calculations core spectra are employed separate out ${\mathrm{Mn}}^{3+}$ ${\mathrm{Mn}}^{4+}$ confirm their relative concentrations. Resonant across $2p\text{\ensuremath{-}}3d$ threshold shows clear enhancement $3d$ partial density two-hole correlation satellites. A Cini-Sawatzky analysis gives on-site Coulomb energy ${U}_{dd}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}\phantom{\rule{4pt}{0ex}}5.5\ifmmode\pm\else\textpm\fi{}0.2$ eV for $3{d}^{n}$ ${U}_{pd}$ = 0.7 $\mathrm{eV}\ifmmode\pm\else\textpm\fi{}0.2$ $3{d}^{n+1}{\underline{L}}^{1}$ states. The O $1s\text{\ensuremath{-}}2p$ is used identify $2p$ satellite provides ${U}_{pp}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}\phantom{\rule{4pt}{0ex}}3.4\ifmmode\pm\else\textpm\fi{}0.2$ Valence band indicates small-gap ($<100$ meV) consistent with electrical transport measurements. estimated parameters energies, combination hybridization strength obtained from model calculations, indicate that ${\mathrm{Tb}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$ strongly correlated type semiconductor.