Induced magnetic two-dimensionality by hole doping in the superconducting infinite-layer nickelate Nd$_{1-x}$Sr$_x$NiO$_2$

TL;DR

This study uses advanced theoretical methods to reveal how hole doping induces two-dimensional magnetic behavior in Nd$_{1-x}$Sr$_x$NiO$_2$, shedding light on its superconducting properties.

Contribution

The paper demonstrates that hole doping enhances two-dimensional magnetic interactions in Nd$_{1-x}$Sr$_x$NiO$_2$, providing new insights into its electronic structure and superconductivity.

Findings

Hole doping suppresses out-of-plane magnetic interactions.

Magnetic two-dimensionality peaks at hole concentration ~0.25.

Undoped NdNiO$_2$ exhibits Fermi-liquid-like behavior.

Abstract

To understand the superconductivity recently discovered in Nd$_{0.8}$Sr$_{0.2}$NiO$_2$, we carried out LDA+DMFT (local density approximation plus dynamical mean-field theory) and magnetic force response calculations. The on-site correlation in Ni-$3d$ orbitals causes notable changes in the electronic structure. The calculated temperature-dependent susceptibility exhibits the Curie-Weiss behavior, indicating the localized character of its moment. From the low-frequency behavior of self-energy, we conclude that the undoped phase of this nickelate is Fermi-liquid-like contrary to cuprates. Interestingly, the estimated correlation strength by means of the inverse of quasiparticle weight is found to increase and then decrease as a function of hole concentration, forming a dome-like shape. Another finding is that magnetic interactions in this material become two-dimensional by hole doping. While the undoped NdNiO$_2$ has the sizable out-of-plane interaction, hole dopings strongly suppress it. This two-dimensionality is maximized at the hole concentration $\delta\approx0.25$. Further analysis as well as the implications of our findings are presented.