Orbital occupancy and hybridization in strained SrVO3 epitaxial films

Abstract

Oxygen packaging in transition metal oxides determines the metal-oxygen hybridization and electronic occupation at metal orbitals. Strontium vanadate $(\mathrm{SrV}{\mathrm{O}}_{3})$, having a single electron in a $3d$ orbital, is thought to be the simplest example of strongly correlated metallic oxides. Here, we determine the effects of epitaxial strain on the electronic properties of $\mathrm{SrV}{\mathrm{O}}_{3}$ thin films, where the metal-oxide sublattice is corner connected. Using x-ray absorption and x-ray linear dichroism at the $\mathrm{V}\phantom{\rule{0.16em}{0ex}}{L}_{2,3}$ and O $K$ edges, it is observed that tensile or compressive epitaxial strain change the hierarchy of orbitals within the ${t}_{2g}$ and ${e}_{g}$ manifolds. Data show a remarkable $2p\ensuremath{-}3d$ hybridization, as well as a strain-induced reordering of the $\mathrm{V}\phantom{\rule{0.16em}{0ex}}3d({t}_{2g},{e}_{g})$ orbitals. The latter is itself accompanied by a consequent change of hybridization that modulates the hybrid ${\ensuremath{\pi}}^{*}$ and ${\ensuremath{\sigma}}^{*}$ orbitals and the carrier population at the metal ions, challenging a rigid band picture.