Resonant inelastic x-ray scattering study of doping and temperature dependence of low-energy excitations in La1−xSrxVO3 thin films

We present a temperature- and doping-dependent resonant inelastic x-ray scattering experiment at the V ${L}_2,3$ and O $K$ edges in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_x{\mathrm{VO}}₃$ thin films with $x=0$ and $x=0.1$. This material is a canonical example of a compound that exhibits a filling-control metal-insulator transition and undergoes orbital ordering and antiferromagnetic transitions at low temperature. Temperature-dependent measurements at the V ${L}₃$ edge reveal an intra-${t}_2g$ excitation that blueshifts by 40 meV from room temperature to 30 K at a rate that differs between the para- and antiferromagnetic phases. The line shape can be partially explained by a purely local model using crystal field theory calculations. For the low Sr concentration $x=0.1$, the doping is shown to affect the local electronic structure primarily on the O sites, beyond a simple Mott-Hubbard picture. Furthermore, the presence of phonon overtone features at the O $K$ edge evidences that the low-energy part of the spectrum is dominated by phonon response.