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Electron correlations and low-energy excitations in perovskite-like vanadium oxides

Owing to the multiple electronic configurations available to the vanadium ion in the solid state, vanadium oxides exhibit complex phase diagrams with competition between charge, spin, orbital and lattice degrees of freedom. Here, we present soft x-ray spectroscopic measurements of two topical perovskite-based vanadium oxides. In RVO3, the near-degeneracy of the ground state leads to a complex interplay between spin and orbital occupation, culminating in unusual orbital order, which we address with resonant inelastic x-ray scattering measurements. On the other hand, the CaxSr1-xVO3 series are prototypical strongly correlated materials that lie close to the Mott-Hubbard transition. Angle-resolved photoemission measurements are employed, alongside first-principles band structure calculations, in an effort to understand the evolution in the correlated behaviour across the series.