Electronic reconstruction in confined SrRuO3 monolayers

We report the observation of an electronic reconstruction in dimensionally controlled ruthenate heterostructures synthesized by pulsed laser deposition. High structural and electronic quality of superlattices comprised of a single SrRuO3 layer inter-spaced with varying thicknesses of insulating SrTiO3 layers was verified by reflection high energy electron diffraction, atomic force microscopy, x-ray diffraction, reciprocal space mapping, and x-ray absorption spectroscopy. X-ray absorption spectroscopy evidences a confinement-driven evolution of the Ru electronic configuration from the d 5 L to the d 4 state. Significant increases of the spin-orbit coupling are observed in connection with the configuration changes supporting recent works identifying large enhancement of the magnetic anisotropy. The growth of high quality two-dimensional confined ruthenate layers under precisely controlled environments highlights the potential to directly manipulate interlayer coupling and selectively perturb the electronic state in ruthenates in analogy to superconducting Sr2RuO4.