Emergence and tunability of Fermi-pocket and electronic instabilities in layered Nickelates

TL;DR

This paper presents a modeling framework for layered Nickelates, revealing how Fermi pockets and electronic instabilities can be tuned by doping and pressure, with implications for high-temperature superconductivity.

Contribution

It introduces a model analyzing the tunability of Fermi pockets and electronic instabilities, emphasizing the role of the $3d_{z^2}$ orbital in layered Nickelates.

Findings

Formation of a second Fermi pocket due to interlayer hybridization.

Susceptibility peaks at wave vector $(\,\pi,\,\pi)$ can be tuned by doping or pressure.

Insights into orbital contributions affecting electronic instabilities.

Abstract

Layered Nickelates have gained intensive attention as potential high-temperature superconductors, showing similarities and subtle differences to well-known Cuprates. This study introduces a modelling framework to analyze the tunability of electronic structures by focusing on effective orbitals and additional Fermi pockets, mimicking doping or external pressure qualitatively. It investigates the role of the $3d_{z^2}$ orbital in interlayer hybridization, which leads to the formation of a second pocket in the Fermi surface. The resulting effective model also predicts specific charge and spin susceptibility in the form of Lindhard susceptibility at wave vector $\mathbf{q_{0}} = (\pi, \pi)$, which can be tuned by doping or pressure. These results provide valuable insights into tunable orbital contributions and their influence on potential ordering and electronic instabilities in Layered Nickelates.