Kondo-like behavior in a mixed valent oxypnictide La₃Cu₄P₄O₂

We have synthesized and characterized the physical properties of a layered, mixed valent oxypnictide [Formula: see text] via magnetization, electrical resistivity, and specific heat measurements. Although [Formula: see text] does not exhibit superconductivity down to T = 0.5 K, it demonstrates an intriguing resistivity minimum observed at [Formula: see text] = 13.7 K. Disappearance of the resistivity minimum under an applied magnetic field of [Formula: see text]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 the Curie-Weiss law observed in the magnetic susceptibility, consistent with the presence of magnetic interactions between paramagnetic [Formula: see text] ions and Kondo screening of these [Formula: see text] 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 [Formula: see text] and isostructural [Formula: see text], which is a superconductor with [Formula: see text] K. Based on the calculations performed, we present the difference between [Formula: see text] and [Formula: see text] in the character of electronic states at the Fermi level. This discrepancy impacts structural stability and may cause a lack of superconductivity in [Formula: see text] down to T = 0.5 K.