High-Temperature Phase Separation and Charge-Magnon Liquid in Kinetic Antiferromagnets

Abstract

Understanding mechanisms of quantum ordering in strongly correlated systems remains a central challenge in condensed matter physics, with implications for designing novel quantum materials. Here, we investigate kinetic antiferromagnetism on a triangular lattice under an applied magnetic field, where spin-polarons emerge as charge-magnon bound states with mutual attraction. Using large-scale diagrammatic Monte Carlo simulations, we show that this interaction drives high-temperature phase separation into charge- and magnon-rich regions, bordered by polarised Mott insulating voids. Spectral function analysis reveals a substantial energy correction from magnon interactions, indicating that these carrier-rich regions form a strongly bound charge-magnon liquid. These findings shed new light on recent experiments on MoTe2/WSe2 moir\'e bilayers, underscoring kinetic magnetism as a unique pathway for strong inter-carrier attraction and high-temperature quantum ordering, with potential applications in quantum materials.