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arXiv · 2503.03447

Kondo-like behavior in a mixed valent oxypnictide $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$

Szymon Królak·Michał J. Winiarski·Duygu Yazici·Soohyeon Shin·Tomasz Klimczuk
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Abstract

We have synthesized and characterized the physical properties of a layered, mixed valent oxypnictide $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$ via magnetization, electrical resistivity, and specific heat measurements. Although $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$ does not exhibit superconductivity down to T = 0.5 K, it demonstrates an intriguing resistivity minimum observed at $\mathrm{T_{min}}$ = 13.7 K. Disappearance of the resistivity minimum under an applied magnetic field of $\mathrm{\mu_{0}H}$ = 9 T together with the negative magnetoresistance at low and positive at high temperatures are observed, which are typical for both Kondo-like spin-dependent scattering and 3D weak localization. We argue that the Kondo scattering is a more plausible explanation due to the low-temperature deviation from a Curie-Weiss law observed in the magnetic susceptibility, consistent with the presence of magnetic interactions between paramagnetic $\mathrm{Cu^{2+}}$ ions and Kondo screening of these $\mathrm{Cu^{2+}}$ moments. We supplemented the experimental characterization with a detailed description of chemical bonding, employing density functional theory (DFT) calculations and crystal orbital Hamilton population (COHP) analysis for $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$ and isostructural $\mathrm{La_{3}Ni_{4}P_{4}O_{2}}$, which is a superconductor with $\mathrm{T_c = 2.2}$ K. Based on the calculations performed, we present the difference between $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$ and $\mathrm{La_{3}Ni_{4}P_{4}O_{2}}$ in the character of electronic states at the Fermi level. This discrepancy impacts structural stability and may cause a lack of superconductivity in $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$ down to T = 0.5 K.

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Szymon Królak, Michał J. Winiarski, Duygu Yazici, Soohyeon Shin, Tomasz Klimczuk. 2025-03-05. Kondo-like behavior in a mixed valent oxypnictide $\mathrm{La_{3}Cu_{4}P_{4}O_{2}}$. https://doi.org/10.1038/s41598-025-89706-6

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