Signatures of Hund's metal physics in single-layered 3d transition metal oxide, Sr₂CoO₄

2025/04/28 by Shivani Bhardwaj, Bhardwaj, Shivani, Sudhir K. Pandey +1
Materials Science · #Advanced Thermoelectric Materials and Devices #Chemical and Physical Properties of Materials #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Strongly Correlated Electrons (cond-mat.str-el)

paper · pdf · doi:10.48550/arxiv.2504.19503

openalex publication_date 2025/04/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

With density functional theory plus dynamical mean-field theory, we study the influence of Hund's coupling on the nature of electronic correlations in Sr₂CoO₄. Our results suggest strong signatures of Hund's metal physics in this compound. The Co 3d states show large orbital differentiation in the degree of correlations and mass enhancement. The imaginary-time correlation functions suggest the presence of spin-orbital separation and large local charge fluctuations in the system. Breakdown of the Fermi-liquid picture is observed at the lowest calculated temperature for various strengths of Hund's coupling, suggesting the Fermi-liquid coherence scale lower than ∼100 K. Interestingly, a sudden emergence of a gapped state is noted for e_g orbitals in its spectral density of states at ∼200 K in the vicinity of Fermi-level. Among the Co 3d states 3d_z² and 3d_x²-y² foster enlarged correlations. This study conclusively identifies Sr₂CoO₄ as the first single-layered 3d transition metal oxide to be classified as Hund's metal.

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