From high Tc to low Tc: Multiorbital effects in transition metal oxides

Despite the structural resemblance of certain cuprate and nickelate parent compounds there is a striking spread of Tc among such transition metal oxide superconductors. We adopt a minimal two-orbital eg model which covers cuprates and nickelate heterostructures in different parametric limits, and analyze its superconducting instabilities. The joint consideration of interactions, doping, fermiology, and in particular the eg orbital splitting allows us to explain the strongly differing pairing propensities in cuprate and nickelate superconductors.