  Oxide heterostructures and superlattices have attracted a great deal of
attention in recent years owing to the rich exotic properties encountered at
their interfaces. We focus on the potential of tunable correlated oxides by
investigating the spectral function of the prototypical correlated metal SrVO3,
using soft x-ray absorption spectroscopy (XAS) and resonant inelastic soft
x-ray scattering (RIXS) to access both unoccupied and occupied electronic
states, respectively. We demonstrate a remarkable level of tunability in the
spectral function of SrVO3 by varying its thickness within the SrVO3/SrTiO3
superlattice, showing that the effects of electron correlation can be tuned
from dominating the energy spectrum in a strongly correlated Mott-Hubbard
insulator, towards a correlated metal. We show that the effects of
dimensionality on the correlated properties of SrVO3 are augmented by
interlayer coupling, yielding a highly flexible correlated oxide that may be
readily married with other oxide systems.
