Correlated electronic structure, orbital-selective behavior, and magnetic correlations in double-layer La\(_3\)Ni\(_2\)O\(_7\) under pressure

Using \emph{ab initio} band structure and DFT+dynamical mean-field theory methods we examine the effects of electron-electron interactions on the normal state electronic structure, Fermi surface, and magnetic correlations of the recently discovered double-layer perovskite superconductor La\(_3\)Ni\(_2\)O\(_7\) under pressure. Our results suggest the formation of a negative charge transfer mixed-valence state with the Ni valence close to 1.75+. We find a remarkable orbital-selective renormalization of the Ni \(3d\) bands, with \(m^*/m \sim 3\) and 2.3 for the Ni \(3z^2-r^2\) and \(x^2-y^2\) orbitals, respectively, in agreement with experimental estimates. Our results for the {\bf k}-dependent spectral functions and Fermi surfaces show significant incoherence of the Ni \(3z^2-r^2\) states, implying the proximity of the Ni \(3d\) states to orbital-dependent localization. Our analysis of the static magnetic susceptibility suggests the possible formation of the spin and charge (or bond) density wave stripe states.