Electronic structure, quasiparticle renormalizations, and magnetic correlations in the alternating single-layer bilayer nickelate La$_5$Ni$_3$O$_{11}$

TL;DR

Using DFT+DMFT, this study explores the electronic structure and magnetic correlations of La$_5$Ni$_3$O$_{11}$, revealing orbital-dependent quasiparticle renormalizations, orbital-selective Mott states, and pressure-induced phase transitions.

Contribution

First detailed DFT+DMFT analysis of La$_5$Ni$_3$O$_{11}$ highlighting orbital-dependent correlations and magnetic instabilities in this nickelate.

Findings

Ni $e_g$ states form strongly renormalized quasiparticle bands with large effective mass enhancements.

Orbital-selective Mott insulating state observed in single-layer Ni ions.

Pressure induces an insulator-to-metal transition, leading to non-Fermi-liquid behavior.

Abstract

Using DFT+DMFT we study the normal-state electronic structure and magnetic correlations of the recently discovered alternating single-layer bilayer Raddlesden-Popper nickelate La$_5$Ni$_3$O$_{11}$ (1212-LNO). Our results exhibit qualitative differences for the structurally distinct single-layer and bilayer Ni ions, implying the importance of confinement and orbital-dependent correlations. The Ni $e_g$ electronic states originating from the bilayer Ni ions form strongly renormalized quasiparticle bands with a large enhancement factor $m^*/m \sim 3.5$ and 4.2 for the Ni $x^2-y^2$ and $3z^2-r^2$ orbitals, respectively. Moreover, the $e_g$ states of the single-layer Ni ions exhibit an orbital-selective Mott insulating state, with a narrow energy gap for the Ni $3z^2-r^2$ states and metallic, strongly incoherent (non-Fermi-liquid) Ni $x^2-y^2$ ones. Our analysis of magnetic correlations suggests the formation of intertwined spin and charge density wave stripes in the bilayer NiO$_6$ slab, in close similarity to the double-layer material. We refine two major instabilities, a leading one is associated with a wave vector ${\bf Q}=(\frac{1}{3},\frac{1}{3})$ (``up-down-0" spin pattern), competing with the bicollinear $(\frac{1}{4},\frac{1}{4})$ (``up-up-down-down") stripe state. The single-layer Ni $3d$ electrons exhibit instability towards the N\'eel-type magnetic state. Under pressure, 1212-LNO undergoes an orbital-selective Mott insulator-to-metal phase transition, associated with metallization of the single-layer Ni $e_g$ states. As a result, the single-layer Ni $e_g$ bands exhibit non-Fermi-liquid (bad metal) behavior with strongly incoherent spectral weights near $E_F$. We note that correlation effects result in a reconstruction of magnetic correlations as compared to that obtained within DFT. In fact, we observe a crossover from single-layer to double-layer dominated magnetic correlations.