Observation of distinct Kondo effect and anomalous Hall effect in V self-intercalated layered antiferromagnet V₅S₈ crystals

Vanadium-based transition metal chalcogenides V_mX_n (X = S, Se, Te) with their distinctive quantum effects, tunable magnetism, spin–orbit coupling, and high carrier mobility are a valuable platform to explore the interplay between magnetism and electronic correlations, especially with tunable structural phases and magnetic properties through stoichiometric variations, making them ideal candidates for advanced device applications. Here, we report the synthesis of high-quality V_5+xS₈ single crystals with different concentrations of self-intercalated vanadium. V_5+xS₈ crystals show an antiferromagnetic behavior and a spin-flop-like transition below T_N of 30.6 K. The high-quality V_5+xS₈ single crystals exhibit a large negative magnetoresistance of 12.3% at 2 K. Interestingly, V_5+xS₈ crystals show an obvious low-temperature resistance upturn that gradually levels off with the increasing magnetic field, attributed to the Kondo effect arising from the interaction between conduction electrons and embedded vanadium magnetic impurities. With increasing V doping, the antiferromagnetic interactions intensify, weakening the coupling between the local moments and conduction electrons, which in turn lowers the Kondo temperature (T_K). Furthermore, the anomalous Hall effect is observed in V_5.73S₈, with an anomalous Hall conductivity (AHC) of 50.46 Ω⁻¹⋅cm⁻¹ and anomalous Hall angle of 0.73% at 2 K. Our findings offer valuable insights into the mechanisms of the Kondo effect and anomalous Hall effect in self-intercalated transition metal chalcogenides with complex magnetism and electronic correlation effects.