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 ${T}_c$ among such transition metal oxide superconductors. We adopt a minimal two-orbital ${e}_g$ 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 ${e}_g$ orbital splitting allows us to explain the strongly differing pairing propensities in cuprate and nickelate superconductors.