Kinetic Magnetism in Triangular Fermi-Hubbard Systems

Kinetically frustrated lattices are predicted to have magnetism driven by itinerant spin polarons — bound states of magnons and charge dopants - even in the absence of superexchange interactions. While signatures of kinetic magnetism have recently been observed in moiré materials, a crucial microscopic investigation is lacking. Here, we present results directly imaging itinerant spin polarons in a triangular lattice Hubbard system using a quantum gas microscope. A full spin-charge readout scheme allows measurement of arbitrary n-point correlation functions above and below half filling. Close to half filling, we find hole dopants locally enhance spiral AFM order, while for charge dopants (doublons) a locally ferromagnetic region is energetically preferable. We study the evolution of these correlations with density and interaction, and are able to use 4-point correlations to show the relative contributions of the kinetic and superexchange magnetisms. We also present new work towards spectroscopic characterization of the system, allowing general measurements of the binding energy and dispersion of quasiparticle excitations in fermionic Hubbard systems.