Correlation-temperature phase diagram of prototypical infinite layer rare earth nickelates

TL;DR

This paper uses dynamical mean-field theory to map the correlation-temperature phase diagram of infinite layer nickelates, revealing phases like Fermi liquid, Curie-Weiss, and antiferromagnetic states, which are relevant for understanding their superconductivity.

Contribution

It provides a new correlation-temperature phase diagram for RNiO2 nickelates, highlighting the interplay of magnetic and electronic phases relevant to superconductivity.

Findings

Identification of a low-temperature Fermi liquid phase

Presence of a high-temperature Curie-Weiss regime

Proximity to an antiferromagnetic dome

Abstract

The discovery of superconductivity in hole-doped infinite layer nickelates, RNiO2 (R = Nd, Pr, La) has garnered sustained interest in the field. A definitive picture of low-energy many-body states has not yet emerged. We provide new insights into the low-energy physics, based on our embedded dynamical mean-field theory calculations, and propose a correlation (U)-temperature (T) phase diagram. The key features are a low-T Fermi liquid (FL) phase, a high-T Curie-Weiss regime, and an antiferromagnetic phase in a narrow U-T region. We associate the onset of the FL phase with partial screening of Ni-d moments; however, full screening occurs at lower temperatures. This may be related to insufficiency of conduction electrons to effectively screen the Ni-d moments, suggestive of Nozieres Exhaustion Principle. Our results suggest that RNiO2 are in the paramagnetic state, close to an antiferromagnetic dome, making magnetic fluctuations feasible. This may be consequential for superconductivity.