Unconventional magnetism and electronic state in frustrated layered system PdCrO$_2$

TL;DR

This study combines first-principles calculations and modeling to explore the unconventional magnetism and electronic states in the frustrated layered material PdCrO₂, revealing factors behind its suppressed Néel temperature and proposing a non-Fermi-liquid state above it.

Contribution

It introduces a comprehensive analysis of PdCrO₂'s magnetic frustration and electronic behavior, proposing a scenario of an exotic non-Fermi-liquid state above the Nél temperature.

Findings

Exchange parameters match experimental Curie-Weiss temperature.

Suppressed Nél temperature due to layered structure and magnetic deformation.

Proposed non-Fermi-liquid state explains main peculiarities.

Abstract

First-principles calculations and a model consideration of magnetically frustrated layered material PdCrO$_2$ are performed. The results on the exchange parameters are in agreement with the experimental data on the Curie-Weiss temperature ($\theta$). We show that experimentally observed strong suppression of the N\'eel temperature ($T_N$) in comparison with the Curie-Weiss temperature is due to three main factors. First, as expected, this is connected with the layered structure and relatively small exchange interaction along the $c$ axis. Second, deformation of the ideal in-plane 120$^{\circ}$ magnetic structure is crucial to provide finite $T_N$ value. However, these two factors are still insufficient to explain low $T_N$ and the large frustration factor $|\theta|/T_N$. Thus, we suggest a scenario of an exotic non-Fermi-liquid state in PdCrO$_2$ above $T_N$ within the frameworks of the Anderson lattice model, which seems to explain qualitatively all its main peculiarities.