Hubbard Subbands and Superconductivity in the Infinite-Layer Nickelate

T. Plienbumrunga, b, M. Daghofera, b, M.T. Schmidc, A.M. Oleśe, d aInstitute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany bCenter for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany cWaseda Research Institute for Science and Engineering, Waseda University, Okubo, Shinjuku, Tokyo, 169-8555, Japan dMax Planck Institute for Solid State Research, Heisenbergstr. 1, D-70569 Stuttgart, Germany eInstitute of Theoretical Physics, Jagiellonian University, Profesora Stanisława Łojasiewicza 11, PL-30348 Kraków, Poland

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An effective two-dimensional two-band model for infinite-layer nickelates consists of bands obtained from dx2-y2 and s-like orbitals. We investigate whether it could be mapped onto a single-band Hubbard model and the filling of Hubbard bands. We find that both one-band physics and a Kondo-lattice regime emerge from the same two-orbital model, depending on the strength of electronic correlations and the filling of the itinerant s-band. Next, we investigate one-particle excitations by changing the screening. First, for weak screening, the strong correlations push electrons out of the s-band so that the undoped nickelate is similar to a cuprate. Second, for strong screening, the s and dx2-y2 bands are both partly filled and weakly coupled. Particularly in this latter regime, mapping to a one-band model gives significant spectral weight transfer between the Hubbard subbands. Finally, we show how the symmetry of superconducting phases depends on the interaction parameters and determine the regions of d-wave or s-wave symmetry.

DOI:10.12693/APhysPolA.143.200 topics: Hubbard model, superconductivity, infinite-layer nickelate