Electronic structure, dimer physics, orbital-selective behavior, and magnetic tendencies in the bilayer nickelate superconductor La3Ni2O7 under pressure

The recently discovered high-temperature superconductor La${}_{3}$Ni${}_{2}$O${}_{7\phantom{\rule{0.333em}{0ex}}}$ with ${T}_{c}$ ~ 80 K under pressure has revolutionized the field of correlated electrons. The authors find here that an orbital-selective spin-singlet ``dimer'' linking the two planes of this bilayer via the ${d}_{3{z}^{2}\ensuremath{-}{r}^{2}}$ orbital provides the primary building block to study its electronic properties. Furthermore, an in-plane robust interorbital hopping between ${e}_{g}$ states, competes with the more natural intraorbital hopping, leading to a dominant spin stripe ($\ensuremath{\pi}$, 0) order, as well as a rich phase diagram.