The interplay of multiorbital physics and nonlocal self-energy effects is studied within an effective three-orbital model for the high-pressure normal state of superconducting bilayer nickelate La3Ni2O7. The model is solved within an advanced many-body framework capturing k-dependent correlations beyond dynamical mean-field theory. Different low-energy scenarios subtly depend on the strength of the interorbital interaction, either placing the notorious flat γ quasiparticle band in the occupied part of the spectrum, or letting it cross the Fermi level. In the latter case, intriguing spin-polaron formation due to the scattering of electrons with paramagnon excitations takes place. This leads to bound states appearing as a shadow band with incoherent low-energy spectral weight below the Fermi level. Our results uncover additional competing states that exist in bilayer nickelates and could explain the controversy of recent angle-resolved photoemission experiments.
@article{arxiv.2604.08221,
title = {Co-operating multiorbital and nonlocal correlations in bilayer nickelate},
author = {Evgeny A. Stepanov and Steffen Bötzel and Ilya M. Eremin and Frank Lechermann},
journal= {arXiv preprint arXiv:2604.08221},
year = {2026}
}