Unconventional magnetism and electronic state in the frustrated layered system PdCrO2

Abstract

First-principles calculations and a model consideration of magnetically frustrated layered material PdCrO2 are performed. The results on the exchange parameters are in agreement with the experimental data on the Curie-Weiss temperature (θ). We show that experimentally observed strong suppression of the Néel temperature (TN) 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° magnetic structure is crucial to provide finite TN value. However, these two factors are still insufficient to explain low TN and the large frustration factor |θ|/TN. Thus, we suggest a scenario of an exotic non-Fermi-liquid state in PdCrO2 above TN within the frameworks of the Anderson lattice model, which seems to explain qualitatively all its main peculiarities. © 2020 American Physical Society.