Correlated electronic structure, orbital-selective behavior, and magnetic correlations in double-layer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>La</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Ni</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math> under pressure
D. A. Shilenko, I. Leonov
Abstract
Using ab initio band structure and $\mathrm{DFT}+\mathrm{dynamical}$ 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 ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$ 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 ${m}^{*}/m\ensuremath{\sim}3$ and 2.3 for the Ni $3{z}^{2}\text{\ensuremath{-}}{r}^{2}$ and ${x}^{2}\text{\ensuremath{-}}{y}^{2}$ orbitals, respectively, in agreement with experimental estimates. Our results for the $k$-dependent spectral functions and Fermi surfaces show significant incoherence of the Ni $3{z}^{2}\text{\ensuremath{-}}{r}^{2}$ states, implying the proximity of the Ni $3d$ states to orbital-dependent localization. Based on our analysis of the static magnetic susceptibility, we propose the possible formation of the spin and charge (or bond) density wave stripe states in high-pressure ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$.