The emergence of quasiparticles in quantum many-body systems underlies the rich phenomenology in many strongly interacting materials. In the context of doped Mott insulators, magnetic polarons are quasiparticles that usually arise from an interplay between the kinetic energy of doped charge carriers and superexchange spin interactions^{1,2,3,4,5,6,7,8}. However, in kinetically frustrated lattices, itinerant spin polarons—bound states of a dopant and a spin flip—have been theoretically predicted even in the absence of superexchange coupling^{9,10,11,12,13,14}. Despite their important role in the theory of kinetic magnetism, a microscopic observation of these polarons is lacking. Here we directly image itinerant spin polarons in a triangular-lattice Hubbard system realized with ultracold atoms, revealing enhanced antiferromagnetic correlations in the local environment of a hole dopant. In contrast, around a charge dopant, we find ferromagnetic correlations, a manifestation of the elusive Nagaoka effect^15,16. We study the evolution of these correlations with interactions and doping, and use higher-order correlation functions to further elucidate the relative contributions of superexchange and kinetic mechanisms. The robustness of itinerant spin polarons at high temperature paves the way for exploring potential mechanisms for hole pairing and superconductivity in frustrated systems^10,11. Furthermore, our work provides microscopic insights into related phenomena in triangular-lattice moiré materials^17,18,19,20.

量子多体系统中准粒子的出现是许多强相互作用材料中丰富现象学的基础。在掺杂莫特绝缘体的情况下，磁极化子是准粒子，通常由掺杂电荷载流子的动能和超交换自旋相互作用之间的相互作用产生^{1,2,3,4,5,6,7,8}。然而，在动力学受挫晶格中，即使在没有超交换耦合的情况下，理论上也可以预测巡回自旋极化子（掺杂剂和自旋翻转的束缚态）^{9,10,11,12,13,14}。尽管它们在动磁理论中发挥着重要作用，但仍缺乏对这些极化子的微观观察。在这里，我们直接对用超冷原子实现的三角晶格哈伯德系统中的巡回自旋极化子进行成像，揭示了空穴掺杂剂局部环境中增强的反铁磁相关性。相反，在电荷掺杂剂周围，我们发现了铁磁相关性，这是难以捉摸的长冈效应的表现^15,16。我们研究这些相关性与相互作用和掺杂的演变，并使用高阶相关函数进一步阐明超交换和动力学机制的相对贡献。高温下巡回自旋极化子的鲁棒性为探索受挫系统中空穴配对和超导的潜在机制铺平了道路^10,11。此外，我们的工作提供了对三角晶格莫尔材料中相关现象的微观见解^17,18,19,20。