Electronic structure, magnetic correlations, and superconducting pairing in the reduced Ruddlesden-Popper bilayer La3Ni2O6 under pressure: Different role of

The authors investigate here two bilayer nickelates under pressure, establishing substantial qualitative differences between the two systems. They find that the ${d}_{3{z}^{2}\ensuremath{-}{r}^{2}}$ orbital in La${}_{3}$Ni${}_{2}$O${}_{6}$ and La${}_{3}$Ni${}_{2}$O${}_{7}$ plays a different role: one ``active'' orbital (${d}_{{x}^{2}\ensuremath{-}{y}^{2}})$ vs two ``active'' orbitals (${e}_{g})$, respectively. The Fermi surface only has two sheets in La${}_{3}$Ni${}_{2}$O${}_{6}$, with the $\ensuremath{\gamma}$ pocket absent, different from La${}_{3}$Ni${}_{2}$O${}_{7}$. They also find that La${}_{3}$Ni${}_{2}$O${}_{6}$ is far from a superconducting instability. Moreover, they do not observe changes in the electronic density in La${}_{3}$Ni${}_{2}$O${}_{6}$ under pressure.